JP2004533522A - Rubber composition for tire containing coupling agent having polythiosulfenamide functional group - Google Patents

Abstract

At least (i) a diene elastomer, (ii) an inorganic filler as a reinforcing filler, and (iii) a (inorganic filler / diene elastomer) coupling agent, at least bifunctional, and Elastomer compositions which can be used in the manufacture of tires based on polysilylated organosilicon compounds which can be grafted onto the elastomer by means of a sulfur group having a sulfenamide function:
(I) ≡ Si − A − S _x − NR ¹ R ²
Wherein A is a linear or branched divalent linking group that allows the polythiosulfenamide group to be linked to the first silicon atom of the organosilicon compound;
x is an integer or a fraction of 2 to 4;
R ¹ represents hydrogen, a monovalent hydrocarbon group or R ² ;
R ² represents the following group;
− B − Si ≡
B is a linear or branched divalent linking group;
Si represents the second silicon atom of the organosilicon compound).
Tires and treads containing compositions of this type.

Description

・N-(3'-トリエトキシシリルプロピルジチオ)-3-トリエトキシシリルプロピルアミン(式V-2)：
【化２】

・式(V-3)のN-メチル-N-(3'-トリエトキシシリルプロピルジチオ)-3-トリメトキシシリルプロピルアミン (Et = エチル；Me = メチル)：
【化３】

【００２９】
本発明のとりわけ好ましい実施態様によれば、上記ポリシリル化ポリチオスルフェンアミドシランは、対称形タイプ(x = y)、即ち、上記式(VI)で示されるようなN原子のいずれかの側に同じ数(2、3または4)のS原子を含むシランである。
この式(VI)において、一方でR⁵、R⁶およびbは、それぞれ、R³、R⁴およびaと同一であり、一方で２つの結合Zが同一であるより特定の場合、厳格に対称形であるそのようなシランは、下記のとりわけ好ましい式を有する：
(VII) [(R⁴O)_a R³ _(3-a) Si − Z − S_x −]₂ N R¹
この式(VII)において、より好ましくは、R¹は、水素、メチル、エチル、プロピル、イソプロピル、ヘキシル、ベンジル、シクロヘキシルおよびフェニルからなる群から選ばれ；Zは、C₁〜C₄アルキレン鎖、より好ましくはプロピレンを示し；基R³およびR⁴は、R³が存在する場合同一または異なるものであり得(a ≠ 3)、より好ましくはC₁〜C₃アルキル、とりわけメチルまたはエチルを示し；xは、より好ましくは2に等しい)。
x = 2である式(VII)の構造を有するオルガノシリコン化合物の例としては、例えば、下記の化合物を挙げることができる：
・式(VII-1)のN,N-ビス(3-トリメトキシシリルプロピルジチオ)シクロヘキシルアミン：
【化４】

・式(VII-2)のN,N-ビス(3-トリエトキシシリルプロピルジチオ)シクロヘキシルアミン：
【化５】

・式(VII-3)のN,N-ビス(3-トリメトキシシリルプロピルジチオ)-3-トリエトキシシリルプロピルアミン：
【化６】

【００３０】
ポリチオスルフェンアミド基を担持する上記の多官能性カップリング剤は、タイヤ用のゴム組成物において使用するジエンエラストマーに対して極めて良好な反応性を示し、そのようなエラストマーとシリカのような補強用無機充填剤とのカップリングにおいてそれ自体で十分に有効であることが判明した。このことに限定することなく、上記多官能性カップリング剤は、本発明のゴム組成物において存在する単独のカップリング剤を有利に構成する。
使用する補強用無機充填剤の比表面積と密度における差異並びに特定的に使用するカップリング剤のモル質量において寛容性を持たせるためには、使用する補強用無機充填剤毎に、補強用無機充填剤の平方メートル当りのモル数において、カップリング剤の最適量を決定するのが好ましい；この最適量は、下記の既知の等式に従い、質量比[カップリング剤/補強用無機充填剤]、充填剤のBET表面積およびカップリング剤のモル質量(以下、Mとして示す)から算出する：
(モル数/m²無機充填剤) = [カップリング剤/無機充填剤] (1/BET) (1/M)
即ち、好ましくは、本発明に従う組成物中で使用するカップリング剤の量は、補強用無機充填剤のm²当り10^-7〜10^-5モルである。さらに好ましくは、カップリング剤の量は、無機充填剤全体の平方メートル当り5 x 10^-7〜5 x 10^-6モルである。
【００３１】
上記で表す量を勘案すると、一般的に、カップリング剤の含有量は、好ましくは1 phrよりも多く、より好ましくは2〜20 phrであろう。示す最低量よりも少ないと、有効リスクが不適切であり、一方、推奨する最高量よりも多いと、カップリングにおけるさらなる改善は一般に観察されず、組成物のコストが上昇する；これらの種々の理由により、このカップリング剤含有量は、さらに好ましくは、3〜12 phrである。
当業者であれば、このカップリング剤含有量は、意図する用途、例えば、本発明の組成物が意図されるタイヤ部品、ジエンエラストマーの性質、使用する補強用無機充填剤の量および当該オルガノシリコン化合物の性質に従って調整し得ることである。
勿論、ゴム組成物のコストを節減するためには、できるだけ少なく、即ち、ジエンエラストマーと補強用無機充填剤間の十分なカップリングのために正しく必要である量を使用するのが好ましい。その有効性により、多くの場合において、補強用無機充填剤量に対して0.5質量％〜20質量％を示す好ましい量で上記カップリング剤を使用することが可能である；15％未満、とりわけ10％未満の量がより好ましい。
最後に、前述のオルガノシリコン化合物は、補強用無機充填剤上に前以ってグラフトさせて(“Y”官能基により)、その後、このような“予備カップリング”させたを遊離の“X”官能基によってジエンエラストマーに結合させ得ることに留意されたい。
【００３２】
II-4. カップリング剤 ( オルガノシリコン化合物 ) の合成
例えば、前述したようなオルガノシリコン化合物は、以下に示す好ましい合成経路(A、BまたはCとして示す方法)に従って調製し得る。
A) 方法“ A ”
X = 2である一般式(IV)(特定の式(V)、(VI)および(VII)を含む)のポリシリル化オルガノシリコン化合物化合物(ジチオスルフェンアミド官能基を有するオルガノシリコン化合物)は、下記の式：
(VIII) (R⁶O)_b R⁵ _(3-b) Si − A − S − S − Hal
（式中、A、R⁵、R⁶およびbは、前記で定義したとおりであり；Halは、ハロゲン(臭素、塩素、フッ素またはヨウ素、好ましくは塩素)である）
のハロゲン化ジスルフィドを、下記の式：
(IX) H N R¹ R²
（式中、R¹およびR²は、前記で定義したとおりである）
の適切なアミン上で、塩基、好ましくは有機塩基の存在下に反応させることによって得ることができる。
適切な塩基は、例えば、N-メチルモルホリン、トリエチルアミン、トリブチルアミン、ジイソプロピルエチルアミン、ジシクロヘキシルアミン、N-メチルピペリジン、ピリジン、4-(1-ピロリジニル)ピリジン、ピコリン、4-(N,N-ジメチルアミノ)ピリジン、2,6-ジ-tert-ブチル-4-メチルピリジン、キノリン、N,N-ジメチルアニリン、N,N-ジエチルアニリン、1,8-ジアザビシクロ[5.4.0]-ウンデセ-7-エン(DBU)、1,5-ジアザビシクロ[4.3.0]-ノン-5-エン(DBN)および1,4-ジアザビシクロ[2.2.2]-オクタン(DABCOまたはトリエチレンジアミン)である。
【００３３】
反応は、好ましくは、エーテル、例えば、ジエチルエーテル、ジイソプロピルエーテル、テトラヒドロフラン、ジオキサン、ジメトキシエタンまたはジエチレングリコールジメチルエーテルのような極性非プロトン性溶媒中で実施する。ジエチレンエーテルが好ましい。
反応温度は、存在する分子の反応性および使用する塩基の力の関数である。この温度は、−78℃〜周囲温度(15〜25℃)で一般に変動する。有利には、−78℃〜−50℃の温度が適している。その後、媒質を周囲温度に戻すのが好ましい。
アミン(IX)が第２級アミンである場合(R¹がH以外)、反応は、化学量論的である；この場合、アミン(IX)対ハロゲン化ジスルフィド(VIII)のモル比は、1〜2、さらに良好には1〜1.5に選定する。
アミン(IX)が第１級アミンである場合(R¹がHを示す)、その使用量は、所望反応生成物の性質による。R¹がHを示す一般式(IV)のオルガノシリコン化合物を得るためには、アミン(IX)は、反応媒質中で過剰である。モル比(IX)/(VIII)は、一般に1〜3で変動し、この比は、一般に1に最も近く、例えば、1〜1.2に選定する。
特定の式(VII)のオルガノシリコン化合物を得るためには、生成物(VIII)対アミン(IX)のモル比を2以上に選定する。このモル比(VIII)/(IX)は、有利には2〜2.3である。この反応において使用する塩基の量は、当業者であれば、容易に決定し得ることであり、塩基は放出するハロゲン化水素酸を捕捉する役割を有する。塩基対式(VIII)の化合物のモル比は、1以上、例えば、1〜3である。
【００３４】
B) 方法“ B ”
X = 2である一般式(IV)(特定の式(V)〜(VII)を含む)のポリシリル化オルガノシリコン化合物は、下記の式：
(X) (R⁶O)_b R⁵ _(3-b) Si − A − S − S − J
（式中、A、R⁵、R⁶およびbは、前記で定義したとおりであり；Jは、必要に応じて置換し得るスクシンイミドまたはフタルイミド基を示す）
のジスルフィドを、上述のアミン(IX)上で、塩基、好ましくは有機塩基の存在下に反応させることによっても得ることができる。スクシンイミドおよびフタルイミド置換基は、使用する反応と両立し得る、即ち、使用する操作条件下において非反応性である有機置換基である。使用し得る塩基は、方法Aにおいて上述した塩基である。
有利には、反応は、非プロトン性極性溶媒、好ましくは脂肪族ハロゲン化炭化水素(塩化メチレンまたは四塩化炭素のような)または必要に応じてハロゲン化した芳香族炭化水素(必要に応じてハロゲン化したベンゼンまたはトルエンのような)中で実施する。好ましくは、上記溶媒はCCl₄である。反応温度は、好ましくは10℃〜100℃、より好ましくは10℃〜50℃である。使用する化合物(IX)と(X)のそれぞれの量は、正しく上述の場合(方法A)におけるように、所望するオルガノシリコン化合物のタイプによる。
従って、(IX)、(X)のモル量および反応させる塩基の決定については、方法Aを参照されたい。
【００３５】
C) 方法“ C ”
X = 2である一般式(IV)(特定の式(V)〜(VII)を含む)のポリシリル化オルガノシリコン化合物は、下記の式：
(XI) J − S − N R¹ R²
（式中、R¹、R²およびJは、前記で定義したとおりである）
のアミノスルフィドを、下記の式：
(XII) (R⁶O)_b R⁵ _(3-b) Si − ^A − SH
（式中、A、R⁵、R⁶およびbは、前記で定義したとおりである）
チオールと、塩基(その塩基は、好ましくは上述したものである)の存在下に反応させることによっても得ることができる。
この反応においては、反応温度は、有利には10〜40℃、より好ましくは15〜30℃、例えば、18〜25℃で変動する。化合物(XI)上での化合物(XII)の反応は、一般に、方法Bの場合において述べたような極性非プロトン溶媒中で実施する。好ましくは、溶媒は、ベンゼンまたはトルエンである。反応は、化学量論反応である。しかしながら、僅かに過剰の化合物(XI)の存在下で操作するのが好ましい。即ち、(XI)対(XII)のモル比は、一般に1〜1.5、さらに良好には1〜1.3である。
この変法Cは、とりわけ、R¹が水素原子以外である一般式(IV)(特定の式(V)〜(VII)を含む)のオルガノシリコン化合物の調製において実施する。
式(VIII)の化合物は、二塩化イオウ(SCl₂)を上述したような式(XII)の適切なメルカプトシラン上で有機塩基の存在下、好ましくはトリエチルアミンの存在下に反応させることによって調製し得る。この反応は、例えば、エーテル中で、−78℃〜−50℃の温度で実施する。有機塩基およびエーテル類は、一般に上述したようなものである。
アミン類(IX)は、市販のアミン類であるか、あるいは市販製品から容易に調製し得る。
【００３６】
式(X)の化合物は、上述したような式(XII)のチオールを、下記の式のハライド上で反応させることによって容易に調製し得る：
(XIII) J − S −Hal
（式中、JおよびHalは、上記で定義したとおりである）。
この反応は、好ましくは、塩基、とりわけ有機塩基の存在下、10℃〜50℃、例えば、15℃〜30℃、とりわけ18℃〜25℃の温度で、方法Bにおいて一般的に述べた極性非プロトン溶媒中で実施する。好ましくは、溶媒は四塩化炭素であり、塩基はトリエチルアミンであり、温度は周囲温度である。この反応は、化学量論的であるが、にもかかわらず、チオール(VII)の不足下で操作するのが好ましい。即ち、化合物(XIII)対化合物(XII)のモル比は、有利には1〜1.5、より良好には1〜1.3である。
式(XI)の化合物は、アミン(IX)を式(XIII)のハライド上で有機塩基の存在下に反応させることによって容易に得られる。この反応は、好ましくは、ハロゲン化炭化水素タイプの溶媒(とりわけ、四塩化炭素)中で、一般に10℃〜50℃、好ましくは15℃〜30℃、例えば18℃〜25℃の温度(周囲温度)で実施する。有機塩基としては、上述した塩基の任意のもの、例えば、トリエチルアミンを選定する。変法においては、塩基として、試薬(IX)を使用し得る。この場合、少なくとも2当量のアミン(IX)を、1当量のハライド(XIII)に対し使用する。
式(XII)の化合物は、市販化合物であり、あるいは市販化合物から容易に調製し得る。
下記の式１は、化合物(XIII)の合成経路を例示する：
【化７】

（式中、JおよびHalは、上記で定義したとおりであり；Mは、アルカリ金属、好ましくはNaまたはKを示す）。
市販化合物(XIV)を、アルカリ金属水酸化物タイプの適切な無機塩基、即ち、M-OH (式中、Mはアルカリ金属である)の作用により、メタノールまたはエタノールのようなC₁〜C₄低級アルコール中でアルカリ金属塩に転換する。この反応は、一般に、15℃〜25℃の温度で生ずる。得られる式(XV)の塩をS₂Cl₂と反応せしめて化合物(XVI)を得る。この反応における有利な反応条件は、ハロゲン化脂肪族炭化水素タイプの極性非プロトン性溶媒(CH₂Cl₂、CCl₄)および−20℃〜10℃の温度である。その後、化合物(XVI)上でのHal-Halの作用により、期待の化合物(XIII)を得る。この後者の工程においては、操作は、好ましくは、ハロゲン化脂肪族炭化水素タイプの極性非プロトン性溶媒(クロロホルムまたはジクロロメタンのような)中での、15℃から溶媒の還流温度までの温度、好ましくは40℃〜80℃、例えば50℃〜70℃においてある。1つの好ましい実施態様によれば、Halは塩素であり、この場合、Hal-Halは反応媒質中にガス形で導入する。
【００３７】
D) 方法“ D ”
X = 3である一般式(IV)(特定の式(V)〜(VII)を含む)のポリシリル化オルガノシリコン化合物は、下記の各工程を組合せることによって得ることができる：
(1) 式(XII)のチオールをS₂(Hal)₂ (式中、Halは、ハロゲン原子、好ましくは塩素を示す)と、塩基、好ましくは有機塩基の存在下に反応させて、下記を得る：
(XVII) (R⁶O)_b R⁵ _(3-b) Si − A − S − S − S − Hal
この反応は、例えば、エーテル中で、−78℃〜−50℃の温度で実施する。有機塩基およびエーテル類は、一般に、方法Aにおいて述べたものである。
(2) 化合物(XVII)を適切な式(IX)のアミン上で塩基、好ましくは有機塩基の存在下に反応させる；さらなる詳細については、方法Aの実施において上述した操作方法を参照し得る。
E) 方法“ E ”
X = 4である一般式(IV)(特定の式(V)〜(VII)を含む)のポリシリル化オルガノシリコン化合物は、下記の各工程を組合せることによって得ることができる：
(1) 式(VIII)のハロゲン化ジスルフィドまたは式(XVII)のハロゲン化トリスルフィドを必要量の元素状イオウと反応させ(化合物(VIII)の場合は2イオウ原子を供給し、化合物(XVII)の場合は1イオウ原子を供給し)、70℃〜170℃の温度で、必要に応じての芳香族溶媒の存在下において操作して、下記の式の化合物を得る：
(XVIII) (R⁶O)_b R⁵ _(3-b) Si − A − S − S − S − S − Hal
(2) 化合物(XVIII)を適切な式(IX)のアミン上で塩基、好ましくは有機塩基の存在下に反応させる；さらなる詳細については、方法Aの実施において上述した操作方法を参照し得る。
【００３８】
II-5. 各種添加剤
勿論、本発明に従うゴム組成物は、例えば、可塑剤；増量剤オイル類；耐オゾン性ワックス、化学耐オゾン剤、酸化防止剤のような保護剤；疲労防止剤；接着促進剤；例えば特許文献１０および１１に記載されているようなカップリング活性化剤；特許文献１２に記載されているような補強用樹脂類；イオウ系、またはイオウおよび/またはパーオキサイドおよび/またはビスマレイミド供与体系のいずれかのような架橋系；加硫促進剤；加硫活性化剤等のような、タイヤ類の製造を意図するジエンゴム組成物において通常使用される添加剤類のすべてまたは同じものも含み得る。また、必要に応じて、通常の補強性に乏しいまたは非補強用の白色充填剤、例えば、クレー、ベントナイト、タルク、チョークまたはカオリンの各粒子も上記補強用無機充填剤と一緒に使用し得る。
本発明に従うゴム組成物は、上述のオルガノシリコン化合物以外に、補強用無機充填剤を被覆するための、例えば、１個の官能基Yを含む薬剤、或いは未硬化状態における加工能力を改善するためのゴムマトリックス中での無機充填剤の分散性改善のためさらにゴム組成物の粘度を低下させるためのより一般的な加工助剤も、公知のとおり含有し得る。これら薬剤は、例えば、アルキルアルコキシシラン類、とりわけ、例えばDegussa-Huls社から商品名Dynasylan Octeoとして市販されている1-オクチルトリエトキシシランまたはDegussa-Huls社から商品名Si216として市販されている1-ヘキサデシルトリエトキシシランのようなアルキルトリエトキシシラン類；ポリオール類；ポリエーテル類(例えば、ポリエチレングリコール類)；第1級、第2級または第3級アミン類(例えば、トリアルカノールアミン類)；ヒドロキシル化または加水分解性ポリオルガノシロキサン類、例えば、α,ω-ジヒドロキシポリオルガノシロキサン類(とりわけ、α,ω-ジヒドロキシポリジメチルシロキサン類)である。
【００３９】
II-6. ゴム組成物の調製
本発明の組成物は、当業者にとって周知の2つの連続する製造段階、即ち、110℃〜190℃、好ましくは130℃〜180℃の最高温度(T_maxと表示)までの高温で熱機械加工または混練する第1段階(時には、“非生産”段階と称する)、その後の、典型的には120℃よりも低い、例えば、60℃〜100℃の低めの温度で機械加工し、この仕上げ段階において架橋または加硫系を混入する第2段階(時には、“生産”段階と称する)を使用して、適切なミキサー内で製造する；そのような各段階は、例えば、前述した特許文献１、３、５、７、１０、１１または１２に記載されている。
本発明に従う組成物の製造方法は、少なくとも上記補強用無機充填剤とオルガノシリコン化合物を、第1のいわゆる非生産段階において、ジエンエラストマー中に混練によって混入させること、即ち、少なくともこれらの各ベース成分をミキサー内に導入し、1以上の工程で、110℃〜190℃、好ましくは130℃〜180℃の最高温度に達するまで熱機械的に混練することに特徴を有する。
【００４０】
例えば、第1の(非生産)段階は、単一の熱機械工程において実施し、その間に、第１段階において、必要なベース成分(ジエンエラストマー、補強用無機充填剤およびオルガノシリコン化合物)すべてを、次いで、第2段階において、例えば1〜2分の混練後、加硫系を除いた任意の追加の被覆剤または加工剤および他の各種添加剤を、通常の密閉式ミキサーのような適切なミキサー内に導入する；補強用無機充填剤の見掛け密度が低い場合(一般に、シリカの場合)、その導入を2以上の部分に分割するのが有利であり得る。第2段階の熱機械加工は、この密閉式ミキサー内で、混合物を落下させた後で且つ中間冷却した後に(好ましくは100℃よりも低い冷却温度)、組成物に補足的な熱処理を受けさせる目的で、とりわけ、補強用無機充填剤とそのカップリング剤とのエラストマーマトリックス内での分散をさらに改善するために追加し得る。この非生産段階における総混練時間は、好ましくは2〜10分間である。
このようにして得られた混合物の冷却後に、加硫系を、低温で、一般的に開放ミルのような開放式ミキサー内で混入する；その後、混合物全体を数分間、例えば、5〜15分間混合する(生産段階)。
その後、このようにして得た最終組成物を、例えば、フィルムまたはシートの形にカレンダー加工するか、或いは、押出加工して、例えば、トレッド、クラウン補強プライ、側壁、カーカス補強プライ、ビーズ、プロテクター、内部チューブまたはチューブレスタイヤ用の気密性内部ゴムのような半製品の製造において使用するゴム形状要素を製造する。
【００４１】
要するに、タイヤ用の半製品の製造において使用し得るエラストマー組成物の製造のための本発明に従う方法は、下記の各工程を含む：
・ミキサー内で、ジエンエラストマー中に、少なくとも：
‐補強用無機充填剤、
‐(無機充填剤/ジエンエラストマー)カップリング剤としての、少なくとも2官能性であり、イオウ基によって上記エラストマー上にグラフトさせ得るオルガノシリコン化合物、
を混入する工程；
・混合物全体を、1以上の工程で、110℃〜190℃の最高温度に達するまで熱機械的に混練する工程；
・混合物全体を100℃未満の温度に冷却する工程；
・次いて、加硫系を混入する工程；
・混合物全体を、120℃未満の最高温度に達するまで混練する工程；
を含み、上記イオウ基は、上記式(I)のポリチオスルフェンアミド官能基を有する基である。
加硫(即ち、硬化)は、公知の方法で、一般的に130℃〜200℃の温度で、好ましくは加圧下に、とりわけ硬化温度、使用する加硫系および当該組成物の加硫速度に依存して変動し得る十分な時間、例えば、5〜90分間で実施する。
適切な加硫系は、好ましくは、イオウと一次加硫促進剤とりわけスルフェンアミドタイプの促進剤とをベースとする。この架橋系に、上記第1の非生産段階中および/または上記生産段階中に、酸化亜鉛、ステアリン酸、グアニジン誘導体(とりわけ、ジフェニルグアニジン)等のような種々の公知の二次促進剤または加硫活性化剤を加え、混入する。イオウは、本発明をタイヤトレッドに応用する場合、好ましくは0.5〜10 phr、より好ましくは0.5〜5.0 phr、例えば、0.5〜3.0 phrの量で使用する。一次加硫促進剤は、とりわけ本発明をタイヤトレッドに応用する場合、好ましくは0.5〜10 phr、より好ましくは0.5〜5.0 phrの量で使用する。
本発明は、“未硬化”状態(即ち、硬化前)および“硬化”即ち加硫状態(即ち、架橋または加硫後)双方の上述のゴム組成物に関する。本発明に従う組成物は、単独で、或いはタイヤ製造において使用することのできる任意の他のゴム組成物とのブレンド(即ち、混合物)において使用することができる。
【発明を実施するための最良の形態】
【００４２】
III. 本発明の実施例
III-1. カップリング剤の合成
本発明の組成物において好ましく使用し得るカップリング剤は、ジチオスルフェンアミドシラン類、より好ましくは式(V-1)〜(V-3)および(VII-1)〜(VII-3)のジチオスルフェンアミドシランに相応するアルコキシシラン類であり、これらの合成方法を、非限定的な実施例により以下に説明する。
摂氏温度(℃)で表す融点(Pf)は、前以って較正した(ΔT = ±2℃)KOFFLER装置上の突起によって測定する。沸点(Eb_pressure)は、ミリバール(mbar)で示す。250MHzプロトン(¹H-NMR)および炭素(¹³C-NMR)スペクトルは、BRUCKER AC 250スペクトロメーター上に記録する。化学シフト(δcおよびδh)は、重クロロホルム(CDCl₃)に対する質量百万分率(ppm)で表す。カップリング定数Jは、Hzで表す。次の略号を使用する：s、一重項；bs、広い一重項；d、二重線；t、三重線；q、四重線；m、多重線。
上記アルコキシシラン類における操作は、すべて不活性雰囲気中および無水条件において実施する。
【実施例１】
【００４３】
この第１の試験においては、N-(3'-トリメトキシシリルプロピルジチオ)-3-プロピルトリエトキシシリル-プロピルアミンを合成する。
400 mlの無水ジエチルエーテル中の100ミリモル(即ち、10.3 g)の二塩化イオウ溶液を、2リットルの三ツ口フラスコ内でアルゴン雰囲気下に−78℃に冷却する。機械攪拌しながら、150 ｍlの無水ジエチルエーテル中の3-メルカプトプロピルトリメトキシシラン(100ミリモル)とトリエチルアミン (100ミリモル、即ち10.2 g)との混合物を滴下により1時間で添加する。反応媒質をこの温度で1時間攪拌し、次いで、100 ｍlの無水ジエチルエーテル中の3-(トリエトキシシリル)-プロピルアミン (110ミリモル)とトリエチルアミン (100ミリモル、即ち10.2 g)との混合物を滴下により1時間で添加する。反応媒質を室温に戻し、その後、トリエチルアミンクロロハイドレートを濾過し、濃縮を減圧下に実施する。減圧下での蒸留により、痕跡量の未反応試薬の除去を可能にする。
NMR分析により、このようにして得られた最終化合物(黄色油状物の外観、収率75％)が上述の特定式(V-1)に相応することを確認する：
【化８】

・¹H NMR (CDCl₃) δ_H
0.62 (t, 2H, Si-CH₂); 0.74 (t, 2H, Si-CH₂); 1.21 (t, 9H, CH₃-CH₂-O);
1.69 (m, 2H, CH₂); 1.82(m, 2H, CH₂); 2.88 (t, 2H, SCH₂);
3.07 (t, 2H, NCH₂); 3.55 (s, 9H, O-CH₃); 3.81 (q, 6H, -OCH₂).
・¹³C NMR (CDCl₃) δ_C
6.2 (Si-CH₂); 9.7 (Si-CH₂); 18.4 (CH₃-CH₂); 20.9 (CH₂); 23.8 (CH₂);
44.0 (S-CH₂); 50.6 (-OCH₃); 54.9 (N-CH₂); 58.5 (-OCH₂)
即ち、下記のとおりである一般式(V)のオルガノキシシラン-ジチオスルフェンアミドを調製した：
‐ R¹ = H；
‐ R² = − Z − Si (OR⁴)₃;
‐ Z = (CH₂)₃ (プロピレン)；
‐ R⁴ = エチル； R⁶ = メチル；
‐ a = b = 3
【実施例２】
【００４４】
同じ操作を実施するが、上記3-メルカプトプロピルトリメトキシシランを3-メルカプトプロピルトリエトキシシランと置換えることによって、NMR分析によって証明されるように、上述の特定式(V-2)のN-(3'-トリエトキシシリルプロピルジチオ)-3-トリエトキシシリルプロピルアミン(黄色油状物の外観、収率86％)を得る：
【化９】

・¹H NMR (CDCl₃) δ_H
0.61 (t, 2H, Si-CH₂); 0.72 (t, 2H, Si-CH₂); 1.21 (m, 18H, CH₃-CH₂-O);
1.69 (2, 2H, CH₂); 1.83 (m, 2H, CH₂); 2.89 (t, 2H, S-CH₂);
3.05 (t, 2H, N-CH₂); 3.81 (m, 12H, -OCH₂).
・¹³C NMR (CDCl₃) δ_C
6.2 (Si-CH₂); 9.7 (Si-CH₂); 18.3 (CH₃-CH₂); 18.4 (CH₃-CH₂);
20.9 (CH₂); 23.8 (CH₂); 44.0 (S-CH₂); 54.9 (N-CH₂); 58.5 (-OCH₂);
58.6 (-OCH₂)
【実施例３】
【００４５】
実施例１の操作を実施するが、上記3-(トリエトキシシリル)-プロピルアミンをシクロヘキシルアミンと置換え、55ミリモルのシクロヘキシルアミンを使用することによって、NMR分析によって証明されるように、上述の特定式(VII-1)のN,N-ビス(3-トリメトキシシリルプロピルジチオ)-シクロヘキシルアミン(オレンジ色油状物の外観、収率85％)を得る：
【化１０】

・¹H NMR (CDCl₃) δ_H
0.73 (m, 4H, Si-CH₂); 1.22 (m, 2H, CH₂); 1.64-1.92 (m, 8H, CH₂);
2.25 (m, 2H, CH₂); 2.40 (m, 2H, CH₂); 2.88 (m, 4H, SCH₂); 3.01 (m, 1H, NCH);3.56 (s, 18H, -OCH₃).
・¹³C NMR (CDCl₃) δ_C
8.3 (2xSi-CH₂); 22.3 (2xCH₂); 26.5 (CH₂); 25.9 (2 x CH₂); 32.7 (2 x CH₂);
41.6 (2xS-CH₂); 50.4 (-OCH₃); 59.9 (N-CH)
即ち、下記のとおりである一般式(VII)のオルガノキシシラン-ジチオスルフェンアミドを調製した：
‐ R¹ = シクロヘキシル；
‐ Z = (CH₂)₃ (プロピレン)；
‐ R⁴ = メチル；
‐ a = 3
【実施例４】
【００４６】
実施例３と同じ操作を実施するが、上記3-メルカプトプロピルトリメトキシシランを3-メルカプトプロピルトリエトキシシランと置換えることによって、NMR分析によって証明されるように、上述の特定式(VII-2)のN,N-ビス(3-トリエトキシシリルプロピルジチオ)シクロヘキシルアミン (オレンジ色油状物の外観、収率90％)を得る：
【化１１】

・¹H NMR (CDCl₃) δ_H
0.75 (t, 4H, Si-CH₂) ; 1.21 (m, 20H, 6xCH₃ and CH₂); 1.62-1.91 (m, 8H, CH₂); 2.25 (m, 2H, CH₂); 2.40 (m, 2H, CH₂); 2.89 (t, 4H, SCH₂); 3.01 (m, 1H, NCH); 3.81 (q, 12H, -OCH₂)
・¹³C NMR (CDCl₃) δ_C
9.6 (2xSi-CH₂); 18.1 (2xCH₃); 22.3 (2xCH₂); 26.5 (CH₂); 26.0 (2 x CH₂);
32.7 (2 x CH₂); 41.5 (S-CH₂); 58.3 (-OCH₂); 59.8 (N-CH)
【実施例５】
【００４７】
実施例３と同じ操作を実施するが、上記シクロヘキシルアミンを3-(トリエトキシシリル)プロピルアミンと置換えることによって、NMR分析によって証明されるように、上述の特定式(VII-3)のN,N-ビス(3-トリエトキシシリルプロピルジチオ)-3-トリエトキシシリルプロピルアミン (黄色油状物の外観、収率87％)を得る：
【化１２】

・¹H NMR (CDCl₃) δ_H
0.62 (t, 2H, Si-CH₂); 0.74 (t, 4H, Si-CH₂); 1.22 (t, 9H, CH₃-CH₂-O);
1.67 (m, 2H, CH₂); 1.83 (m, 4H, CH₂); 2.82 (t, 4H, S-CH₂);
3.05 (m, 2H, CH₂); 3.55 (s, 18H, O-CH₃); 3.80 (q, 6H, -OCH₂).
・¹³C NMR (CDCl₃) δ_C
6.2 (Si-CH₂); 9.7 (Si-CH₂); 18.4 (CH₃-CH₂); 20.9 (CH₂); 23.8 (CH₂);
44.0 (S-CH₂); 50.6 (-OCH₃); 54.9 (N-CH₂); 58.5 (-OCH₂)
【実施例６】
【００４８】
この試験においては、式(V-3)のN-メチル-N-(3'-トリエトキシシリルプロピルジチオ)-3'-トリメトキシシリルプロピルアミンを3工程において合成する。
a) フタルイミドスルフェニルクロライド：
磁力攪拌器を備えた三ツ口フラスコ内の350 mlクロロホルム中の0.1モル(35.6 g)のフタルイミドジスルフィド懸濁液を60℃に加熱する。塩素ガス流を、完全溶解が生ずるまで通す。反応媒質を周囲温度に戻し、次いで、溶媒を減圧下に蒸発させる。得られたフタルイミドスルフェニルクロライドをジクロロメタン中で再結晶化する。
収率；99%
外観：黄色結晶
融点：114℃
¹H NMR (CDCl₃) δ_H :
7.90 (m, 芳香族 2H); 8.01 (m, 芳香族 2H).
¹³C NMR (CDCl₃) δ_C：
124.7 (2 芳香族 CH); 131.6 (2 芳香族 C);
135.6 (2 CH 芳香族); 165.8 (2 C=O).
b) N-(N'- メチル -N'-3- トリメトキシシリルプロピル ) アミノチオフタルイミド：
上記フタルイミドスルフェニルクロライド(0.1モル、即ち、21.35 g)を、磁力攪拌器を備えた三ツ口フラスコ内で、不活性雰囲気中で350 mlのクロロホルム中に溶解させる。50 mlのクロロホルム中に希釈した0.21モルのN-メチル-N-(3-トリメトキシシリルプロピル)アミンを、周囲温度で滴下によって添加する。混合物を3時間攪拌し、次いで、溶媒を蒸発させる。混合物をジエチルエーテルで処理し、上記アミンのクロロハイドレートを濾過し、次いで、減圧下に濃縮させる。
収率：88%
外観：オレンジ色油状物
¹H NMR (CDCl₃) δ_H
0.64 (t, 2H, Si-CH₂); 1.78 (m, 2H, CH₂); 2.93 (H₃C-N);
3.05 (t, 2H N- CH₂); 3.56 (s, 9H -OCH₃); 7.77 (m, 芳香族 2H);
7.92 (m, 芳香族 2H).
¹³C NMR (CDCl₃) δ_c
5.9 (SiCH₂); 21.0 (CH₂); 46.8 (N-CH₃); 50.5 (-OCH₃);
62.9 (N-CH₂); 123.8 (2 芳香族 CH); 132.3 (2 芳香族 C);
134.2 (2 芳香族 CH); 169.5 (2 C=O)
【００４９】
c) N- メチル -N-(3'- トリエトキシシリルプロピルジチオ )-3'- トリメトキシシリルプロピルアミン：
上記の工程で得られたスルフィド(50ミリモル)を、磁力攪拌器を備えた三ツ口フラスコ内で、不活性雰囲気中で250 mlのベンゼン中に溶解させる。最小量のベンゼン中に希釈した3-メルカプトプロピルトリエトキシシラン(45ミリモル)を１度に添加する。これを、周囲温度で攪拌しながら48時間放置する。沈殿したフタルイミドと過剰のスルフィドを濾別し、次いで、溶媒を減圧下に蒸発させた。
NMR分析によって証明されるように、上述の特定式(V-3)のN-メチル-N-(3'-トリエトキシシリルプロピルジチオ)-3'-トリメトキシシリルプロピルアミン(黄色油状物の外観、収率95％)を得る：
【化１３】

・¹H NMR (CDCl₃) δ_H
0.61 (t, 2H, Si-CH₂); 0.72 (t, 2H, Si-CH₂); 1.22(t, 9H, CH₃); 1.68 (m, 2H, CH₂); 1.80 (m, 2H, CH₂); 2.68 (NCH₃); 2.75 (t, 2H, CH₂); 2.88 (t, 2H, CH₂); 3.57 (s, 9H, -OCH₃); 3.82 (q, 6H, O-CH₂).
・¹³C NMR (CDCl₃) δ_C
6.2 (Si-CH₂); 9.7 (Si-CH₂); 18.4 (CH₃-CH₂); 20.9 (CH₂); 23.8 (CH₂);
44.0 (S-CH₂); 46.1 (-NCH₃); 50.6 (-OCH₃); 58.5 (-OCH₂); 60.9 (N-CH₂)
即ち、下記のとおりである一般式(V)のジチオスルフェンアミドオルガノキシシランを得た：
‐ R¹ = メチル；
‐ R² = − Z − Si (OMe)₃;
‐ Z = (CH₂)₃ (プロピレン)；
‐ R⁴ = メチル； R⁶ = エチル；
‐ a = b = 3
【００５０】
III-2. ゴム組成物の調製
以下の各試験において、手順は次のとおりである：ジエンエラストマー(または、必要に応じてのジエンエラストマー混合物)、補強用充填剤、カップリング剤を、次いで、1〜2分間の混練後に、加硫系を除く他の各種添加剤を密閉式ミキサーに入れ、70%まで満す。ミキサーの初期タンク温度は約60℃である。その後、熱機械加工(非生産段階)を、約165℃の最高“落下”温度に達するまで、2工程で実施する(総混練時間約7分)。このようにして得た混合物を回収し、冷却し、次いで、加硫系(イオウとスルフェンアミド促進剤)を、30℃の開放型ミキサー(ホモ-フィニッシャー)で、すべてを3〜4分間混合する(生産工程)ことによって添加する。
その後、このようにして得た組成物を、その物理特性または機械特性を測定するためのゴム薄スラブ(2〜3 mm厚)または薄シートの形に、あるいは所望寸法に切断しおよび/または組み立てた後に、例えば、タイヤ類用の半製品、とりわけタイヤ用のトレッドとして直接使用できる形状要素にカレンダー加工する。
以下の試験において、補強用無機充填剤(HDシリカ)は、50〜100 phr範囲内の好ましい量で使用する補強用充填剤全体を構成する；しかし、補強用充填剤の1部、好ましくは小割合をカーボンブラックで置換え得ることは、当業者にとっては言うまでもないことである。
【００５１】
III-3. ゴム組成物の特性決定
この試験の目的は、通常のTESPTカップリング剤を使用する従来技術の組成物と比較して、本発明に従う組成物における改良された(無機充填剤/ジエンエラストマー)カップリング性能を例証することである。
‐組成物C-1：通常のTESPTシラン
‐組成物C-2：式VII-2のシラン-ジチオスルフェンアミド。
TESPTは、式：[(C₂H₅O)₃Si(CH₂)₃S₂]₂を有するビス(3-トリエトキシシリルプロピル)テトラスルフィドであることを再認識されたい；TESPTは、例えば、Degussa社から商品名“Si69”(または、カーボンブラック上に50質量％まで支持されている場合には、“X50S”)として、或いはWitco社から商品名“Silquest A1289”として市販されている(双方とも、4に近い平均ｘ値を有するポリスルフィドS_xの市販混合物)。
TESPTの構造式は、下記のとおりである：
【化１４】

この式を、下記の式VII-1のジチオスルフェンアミドシランの式と比較すべきである：
【化１５】

上記２つの化学構造体の１部は同一であり(Y官能基と炭化水素基Z(この場合、プロピレン鎖)、YとXの結合を可能にしている)、唯一の差異は、ジエンエラストマー上にグラフトさせ得るイオウ化官能基(X官能基)の本質にある：通常の組成物用のポリスルフィド基Sxと本発明の組成物用のポリチオスルフェンアミド基。
【００５２】
表１は、上記２つの組成物の配合を示しており(各種製品の量はphrで表している)；加硫系は、イオウとスルフェンアミドからなっている。
上記２つのカップリング剤は、この場合、シリコンの等モル量で使用している、即ち、組成物の如何にかかわらず、シリカおよびそのヒドロキシル表面基に対して反応性であるY官能基(この場合、Y = Si(OEt)₃)を同じモル数で使用している。
補強用無機充填剤の量に対しては、カップリング剤の量は、双方共、10 phr未満であり、この量は補強用無機充填剤量に対し１５質量％未満を示す。
図１および２は、それぞれ、レオグラム(硬化時間(分)の関数としてのトルク(dN.m)および硬化(150℃で40分)後の、伸び(％)の関数としてのモジュラス(MPa)曲線を再生させている；これらの曲線は、図１においてはC1およびC2として、図２においてはC1'およびC2'として印しており、それぞれ、組成物C-1およびC-2に相応する。
先ず第1に、図１のレオグラムは、本発明の組成物C-2の優位性を明白に示している：対照組成物の誘導時間(前記I-3の項に従って測定後7.5分)に近い誘導期間(5.1分)；対照組成物の最高トルク(測定後18 dN.m)よりも大きい最高トルク(19 dN.m)；最後に、何にましても、30％〜80％の転換率において明らかに顕著であるレオグラム勾配(定数K)によって例証されるように、明白に速い加硫速度(測定値(前記I-3の項に従う)は、組成物C-2において、対照組成物において記録した勾配(K = 0.13 min^-1)の実質2倍のK = 0.22 min^-1を示している)；換言すれば、組成物C-2の硬化は、より短時間で実施し得る。
硬化後(図２)、本発明の組成物(曲線C2)は、対照組成物(曲線C1)と比較して、実質的に同等である破壊時特性；しかし、とりわけ高変形(100％以上の伸び)において明らかに優れている補強(モジュラス)値；伸びが増大するにつれて、すべてより明白となる２つの曲線間の距離を明白にしている。そのような挙動は、補強用無機充填剤とジエンエラストマー間の改良されたカップリング性を明らかに例証しており、本発明組成物の磨耗に耐える極めて良好な能力を期待するのを可能にしている。
さらにまた、対照組成物においてもすでに低いムーニー可塑度が、本発明の組成物においては予想外に低下しており(10％近く)、もう１つの利点として、本発明組成物の未加硫状態での優れた加工能力が立証されている。
【産業上の利用可能性】
【００５３】
結論として、本発明に従う組成物用に選定したカップリング剤は、後での高補強特性、未硬化状態での優れた加工特性および極めて良好な加硫能力を与えており、補強用シリカのような無機充填剤で補強したジエンゴム組成物における参照の(無機充填剤/エラストマー)カップリング剤として依然として現在もみなされているTESPTの有効性よりも全体的に高い有効性を明白にしている。
本発明は、低転がり抵抗性と高耐摩耗性の双方を有するタイヤ用のトレッド類の製造を意図するゴム組成物において、とりわけこれらのトレッド類を旅客車両、モーターサイクル類または重量車両タイプのような産業用車両用のタイヤ用に意図する場合に、とりわけ有利に応用することができる。
【００５４】
表 1

(1) 59.5%の1-2ポリブタジエン単位、26.5%のスチレンを含むSSBR；Tg = -29℃；
芳香族オイルでの75 phr乾燥SBR増量(SSBR + オイルの総量が103 phrに等しい)。
(2) 4.3%の1-2、2.7%のトランス、93%のシス1-4を含むBR (Tg = -106℃)。
(3) マイクロビーズ形のRhodia社からのシリカタイプ “HDS”-Zeosil 1165 MP
(BETおよびCTAB：約150〜160 m²/g)。
(4) TESPT (Degussa社からの“Si69”)。
(5) 式VII-2のシラン-ジチオスルフェンアミド(III-1項、実施例４に従って合成)；
(6) ジフェニルグアニジン (Bayer社からの“Vulcacit D”)。
(7) N-シクロヘキシル-2-ベンゾチアジルスルフェンアミド(Flexsys社からの
“Santocure CBS”)。
【図面の簡単な説明】
【００５５】
【図１】本発明に従うまたは従わないゴム組成物において記録したレオグラム(硬化曲線)である。
【図２】これらのゴム組成物における伸びの関数としてのモジュラスの変化曲線である。【Technical field】
[0001]
The present invention relates to diene elastomer compositions intended for the manufacture of tires or semi-finished products for tires, in particular treads for these tires, reinforced with white or inorganic fillers.
More particularly, the invention relates to the use of a binder in such a composition for coupling a reinforcing inorganic filler with a diene elastomer.
[Background Art]
[0002]
In order to obtain the optimal reinforcing properties provided by the filler, the filler must be present in the elastomeric matrix in both final forms, as finely divided as possible and distributed as homogeneously as possible. That is generally known. At present, such conditions have the very good ability that the filler firstly mixes into the elastomer matrix during mixing with the elastomer, disaggregates and secondly disperses homogeneously in this matrix. You can only get it as long as you have it.
It is well known that carbon black has such a capability, but this is not generally the case for inorganic fillers. This is because the inorganic filler particles have an exciting propensity to aggregate together within the elastomeric matrix to attract each other. These interactions can be achieved theoretically, assuming that all of the (inorganic filler / elastomer) bonds that can occur during the mixing operation have actually been obtained, due to the dispersibility, and thus the reinforcing properties, of the inorganic filler. It has the deleterious consequence of constraining to levels substantially lower than would have been. These interactions also tend to increase the viscosity of the uncured rubber composition, thus making processing ("processability") of those rubber compositions more difficult than in the presence of carbon black. I have to.
However, as fuel economy and the need for environmental protection have become a priority, the need to produce tires with reduced rolling resistance without adversely affecting wear resistance has become apparent. I have. This has been made possible in particular on the basis of the discovery of new rubber compositions reinforced with certain inorganic fillers called "reinforcing" fillers, which fillers, from the point of view of reinforcement, are not suitable for conventional tires. These compositions also antagonize low-grade hysteresis, which is synonymous with low rolling resistance in tires containing the rubber composition, and also very good on wet, snowy or frozen ground It can give good grip characteristics.
[0003]
For example, such rubber compositions containing reinforcing inorganic fillers of the silica or aluminum type have been disclosed (see patent documents 1 to 12).
Among other things, Patent Documents 1, 2 and 7 disclose diene rubber compositions reinforced with precipitated silica having high dispersibility, and such compositions have significantly improved rolling resistance. Treads having good properties can be produced without adversely affecting other properties, in particular, grip properties, durability and abrasion resistance. Such a composition having such a compromise of conflicting properties is also described in US Pat. No. 5,077,045 with certain aluminas having high dispersibility as reinforcing inorganic fillers.
Although the use of these particular highly dispersible inorganic fillers has reduced the difficulty of processing the rubber compositions containing these fillers in an uncured state, such rubber compositions are still still carbon It is more difficult to process than in black filled rubber compositions.
In particular, it is necessary to use a coupling agent, also called a binder. The function of the coupling agent is to provide a bond between the inorganic filler particle surface and the diene elastomer while facilitating the dispersion of the inorganic filler within the elastomer matrix.
[0004]
(Inorganic filler / elastomer) The term "coupling agent" is understood to mean a compound capable of establishing a sufficient chemical and / or physical bond between an inorganic filler and a diene elastomer. It should be understood that such coupling agents are at least bifunctional and have, for example, the general formula "YTX", wherein:
Y can be physically and / or chemically bonded to the inorganic filler, such that the bond is formed between, for example, the silicon atom of the coupling agent and the surface hydroxyl (OH) group of the inorganic filler (e.g., in the case of silica). Surface silanols) (functional groups "Y");
X represents a functional group ("X" functional group) capable of physically and / or chemically bonding to the diene elastomer, for example, by a sulfur atom;
T is a divalent organic group capable of binding Y and X.
These coupling agents are, inter alia, for coating inorganic fillers which can contain in a known manner a function Y which is active on inorganic fillers but which do not contain a function X which is active on diene elastomers. Should not be confused with simple drugs.
Coupling agents, especially (silica / diene elastomer) coupling agents, are described in a large number of documents, the best known being the three organoxysilyl (especially alkoxysilyl) as "Y" functional groups. 2.) Bifunctional organosilanes which carry at least one group capable of reacting with a diene elastomer, such as, inter alia, a sulfur function, ie a sulfur function, as an X function.
[0005]
That is, it has been proposed to use a mercaptoalkoxysilane coupling agent in the production of treads for tires (see Patent Documents 13 and 14). That their mercaptoalkoxysilanes can provide excellent silica / elastomer coupling properties, however, these coupling agents are highly reactive with the thiol-type sulfur functional group -SH ("X" functional group) Therefore, it was quickly found that it could not be used industrially, and it is well known today. This high reactivity causes very rapid premature vulcanization (also known as "scorching") at very high viscosities in the uncured state during the preparation of rubber compositions in internal mixers. And finally results in a rubber composition that is practically impossible to process and process industrially. To exemplify this problem, reference can be made, for example, to US Pat.
To overcome this drawback, it has been proposed to replace these mercaptoalkoxysilanes with polysulfided alkoxysilanes, especially bis- (alkoxysilylpropyl) polysulfides as described in many documents. (See, for example, Patent Documents 18, 15, 19, 16 and 20). Of these polysulfides, bis-3-triethoxysilylpropyl tetrasulfide (abbreviated as TESPT) and bis-3-triethoxysilylpropyl disulfide (abbreviated as TESPD) have to be mentioned especially.
These polysulfurized alkoxysilanes, especially TESPT, offer the best compromise in scorch resistance, ease of processing and reinforcement in vulcanized rubber compositions containing reinforcing inorganic fillers, especially silica. Products are generally considered to be Thus, even though polysulfurized alkoxysilanes have the known disadvantage of being relatively expensive and most often having to be used in relatively large amounts (see, for example, US Pat. It is currently the most used coupling agent in rubber compositions for tires.
[0006]
[Patent Document 1]
EP-A-0 501 227
[Patent Document 2]
U.S. Pat.No. 5,227,425
[Patent Document 3]
EP-A-0 735 088
[Patent Document 4]
U.S. Patent No. 5,852,099
[Patent Document 5]
EP-A-0 810 258 No.
[Patent Document 6]
US Patent 5,900,449
[Patent Document 7]
EP-A-0 881 252
[Patent Document 8]
WO99 / 02590
[Patent Document 9]
WO99 / 06480
[Patent Document 10]
WO00 / 05300 No.
[Patent Document 11]
WO00 / 05301
[Patent Document 12]
WO02 / 10269
[Patent Document 13]
Patent application FR-A-2094859
[Patent Document 14]
Patent application GB-A-1310379
[Patent Document 15]
FR 2 206 330
[Patent Document 16]
U.S. Patent No. 3,873,489
[Patent Document 17]
U.S. Patent No. 4,002,594
[Patent Document 18]
FR 2 149 339
[Patent Document 19]
U.S. Patent No. 3,842,111
[Patent Document 20]
U.S. Patent No. 3,997,581
[Patent Document 21]
U.S. Patent No. 5,652,310
[Patent Document 22]
U.S. Patent No. 5,684,171
[Patent Document 23]
U.S. Patent No. 5,684,172
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0007]
This time, contrary to expectations, during the course of the study, the applicant found that a specific coupling agent, in rubber compositions for tires, had better coupling performance than polysulfided alkoxysilanes, especially the performance of TESPT. Has been found to be possible.
These coupling agents are organosilicon compounds having the essential feature of carrying a specific polythiosulfenamide functional group as the X functional group. Furthermore, these organosilicon compounds have the above-mentioned scorch and processability problems associated with the excessive viscosity of the rubber composition in the unvulcanized state (these disadvantages are found especially in mercaptosilanes). Absent.
[Means for Solving the Problems]
[0008]
Accordingly, a first subject of the present invention is that at least (i) a diene elastomer, (ii) an inorganic filler as a reinforcing filler and (iii) a (inorganic filler / diene elastomer) coupling agent as base components. An elastomer composition useful in the manufacture of tires, comprising a polysilylated organosilicon compound that is at least bifunctional and can be grafted onto the elastomer by a sulfur group having a polythiosulfenamide functional group of the formula :
(I) ≡ Si − A − S_x − N R¹ R^Two
Wherein A is a linear or branched divalent linking group that enables the polythiosulfenamide group to be linked to the first silicon atom of the organosilicon compound;
x is an integer or a fraction of 2 to 4;
R¹Is hydrogen, a monovalent hydrocarbon group or R^TwoShows;
R^TwoRepresents the following groups:
− B − Si ≡
B is a linear or branched divalent linking group;
Si represents the second silicon atom of the organosilicon compound).
Another subject of the invention is the use of the rubber compositions according to the invention in the manufacture of tires and in the manufacture of semi-finished products for such tires, these semi-finished products being, inter alia, treads, such as these treads Underlayers, crown reinforcement plies, sidewalls, carcass reinforcement plies, beads, protectors, inner tubes and hermetic inner rubbers for tubeless tires.
[0009]
Further subjects of the present invention are the above-mentioned tires and the above-mentioned semi-finished products themselves comprising the elastomer composition according to the invention, these tires being passenger vehicles, 4x4 vehicles (with 4 drive wheels), SUVs ("Sport utility vehicles"), two-wheeled vehicles (especially bicycles or motorcycles); and also vans, "heavy vehicles" (i.e. subway trains, buses, road transport machinery (truck, It is intended to fit into industrial vehicles selected from tractors, trailers), off-road vehicles (agricultural or construction machinery), aircraft and other transport or operating vehicles.
The invention relates in particular to treads for tires, which can be used in the manufacture of new tires or in the recapping of worn tires; because of the composition of the invention, these treads have all of the following properties: Has: low rolling resistance, very good grip and high abrasion resistance.
The present invention also relates to a method for producing a rubber composition useful in producing tires, and the method comprises the following steps:
-In a mixer, in a diene elastomer, at least:
-Inorganic filler for reinforcement,
-A polysilylated organosilicon compound that is at least bifunctional and can be grafted onto the elastomer by a sulfur group, as a (inorganic filler / diene elastomer) coupling agent;
Mixing step;
Thermomechanically kneading the whole mixture in one or more steps until a maximum temperature of 110 ° C to 190 ° C is reached;
Cooling the whole mixture to a temperature below 100 ° C .;
・ Next, a step of mixing a vulcanization system;
Kneading the entire mixture until a maximum temperature of less than 120 ° C. is reached;
Wherein the sulfur group satisfies the above formula (I).
[0010]
A further subject of the invention is a polythiosulfenamide of the formula (I) described above, which is at least difunctional in a composition based on a diene elastomer reinforced by an inorganic filler intended for the manufacture of tires. Use of an organosilicon compound which can be grafted onto the elastomer by means of a sulfur group having a functional group as a (inorganic filler / diene elastomer) coupling agent.
Finally, the subject of the present invention relates to a method for coupling an inorganic filler and a diene elastomer in an elastomer composition useful in the manufacture of tires, which method comprises the following steps:
-In a mixer, in a diene elastomer, at least:
-Inorganic filler for reinforcement,
-An organosilicon compound which is at least difunctional and can be grafted onto the elastomer by means of sulfur groups, as (inorganic filler / diene elastomer) coupling agent,
Mixing step;
Thermomechanically kneading the whole mixture in one or more steps until a maximum temperature of 110 ° C to 190 ° C is reached;
Cooling the whole mixture to a temperature below 100 ° C .;
Wherein the sulfur group satisfies the above formula (I).
The present invention and its advantages will be readily understood in light of the following description and examples, and the accompanying drawings associated with these examples.
[0011]
I. Measurements and test methods used
Each rubber composition is characterized before and after curing, as described below.
I-1. Mooney plasticity
An oscillating consistency meter as described in the French Standard NF T 43-005 (1991) is used. Mooney plasticity is measured according to the following principle: The uncured composition (ie, before curing) is molded in a cylindrical enclosure heated to 100 ° C. After one minute of preheating, the rotor is rotated at 2 rpm in the specimen and the torque used to maintain this motion is measured after four minutes of rotation. Mooney plasticity (ML 1 +4) is expressed in “Mooney units” (MU, 1 MU = 0.83 Newton-meter).
I-2 Scorch time
The measurement is performed at 130 ° C. according to the French standard NF T 43-005 (1991). The expansion of the consistency measurement factor as a function of time is evaluated according to the above standard with parameter T5 (for large rotors), expressed in minutes, and the consistency measurement factor (in MU) 5 units higher than the lowest value measured in this factor. It is possible to measure the scorch time in the rubber composition, defined as the time required to obtain an increase in (indication).
[0012]
I-3. Flow rate measurement
The measurement is carried out at 150 ° C. using a shaking chamber rheometer according to DIN standard 53529-part 3 (June 1983). The evolution of the rheometry torque as a function of time explains the evolution of the stiffening of the composition after the vulcanization reaction (see FIG. 1). The measurements are processed in accordance with DIN Standard 53529-Part 2 (March 1983): t_iIs the induction time, ie, the time required for the vulcanization reaction to commence; t_α(For example, t₉₀Or t₉₉) Is the conversion required of α%, ie the time required to obtain the deviation α% between the minimum torque value and the maximum torque value (eg, 90% or 99%, respectively). Conversion rate constant of order 1 calculated between 30% conversion and 80% conversion K (min^-1) Is also measured, so that the vulcanization rate can be evaluated.
I- 4 Tensile test
These tests allow measurement of elastic stress and properties at break. Unless otherwise stated, these tests are performed according to the French Standard NF T 46-002 of September 1988. The nominal secant modulus (or apparent stress, in MPa) at 10% elongation (ME10), 100% elongation (ME100) and 300% elongation (ME300) is measured at the second elongation (ie, after the conditioning cycle). The breaking stress (in MPa) and elongation at break (in%) are also measured. All these tensile measurements are carried out under defined conditions of defined temperature (23 ± 2 ° C.) and humidity (50 ± 5% relative humidity) according to the French standard NF T40-101 (December 1979).
By processing the recorded tensile data, it is also possible to trace the modulus curve as a function of elongation (see Figure 2), where the modulus is measured at the first elongation and the true It is a true secant modulus not calculated based on the conventional initial cross section at the nominal modulus, calculated by reducing to the cross section.
[0013]
II. Conditions for practicing the present invention
The rubber composition according to the invention is based on at least the following components: (i) (at least one) diene elastomer, (ii) (at least one) inorganic filler as reinforcing filler, ( iii) (at least one) specific organosilicon compound as (inorganic filler / diene elastomer) coupling agent.
Of course, the expression "based on" composition is to be understood as meaning a composition comprising the above-mentioned mixture and / or the in-situ reaction product of each of the above-mentioned components used, some of these base components being It is intended to have or react to react at least partially together during the various stages of the preparation of the composition of the invention, in particular its vulcanization.
[0014]
II-1 Diene elastomer
As known, "diene" elastomers or rubbers are elastomers (i.e., monomers having two double carbon-carbon bonds, whether conjugated or unconjugated) derived from diene monomers (i.e., , Homopolymers or copolymers).
Generally, "essentially unsaturated" diene elastomers are obtained herein from at least one part of conjugated diene monomers and have a diene source (conjugated dienes) having a content of 15% (units) or units. (Mol%) is understood to mean more diene elastomers.
Thus, for example, diene elastomers, such as butyl rubber or copolymers of EPDM-type dienes with alpha-olefins, do not fall under the above definitions, and in particular, are "essentially saturated" diene elastomers (always Low or very low diene originating unit content of less than 15%).
In the category of "essentially unsaturated" diene elastomers, "highly unsaturated" diene elastomers mean, among others, diene elastomers having a unit content of diene origin (conjugated dienes) of more than 50%. I want to be understood.
In view of the above definitions, the following elastomers are to be understood as meaning, inter alia, diene elastomers which can be used in the composition according to the invention:
(a) any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 12 carbon atoms;
(b) any copolymer obtained by copolymerization between one or more conjugated dienes or with one or more vinyl aromatic compounds having 8 to 20 carbon atoms;
(c) ethylene, e.g., an elastomer obtained from ethylene, propylene and a non-conjugated diene monomer of the type described above, especially 1,4-hexadiene, ethylidene norbornene or dicyclopentadiene, 3-6 carbon atoms. Three-component copolymers obtained by copolymerization of α-olefins having atoms with non-conjugated diene monomers having 6 to 12 carbon atoms;
(d) Copolymers of isobutene and isoprene (butyl rubber), and also halogenated, especially chlorinated or brominated, forms of this type of copolymer.
[0015]
Although the present invention applies to any type of diene elastomer, especially when the above rubber composition is intended as tire treads, the present invention is first and foremost essentially unsaturated diene elastomers, especially the type (a) described above. Or what is used in the elastomer of (b) can be understood by those skilled in the tire technology.
Suitable conjugated dienes are, among others, 1,3-butadiene; 2-methyl-1,3-butadiene; for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene 2,3-di (C such as 2-methyl-1,3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene₁~ C_FiveAlkyl) -1,3-butadienes; aryl-1,3-butadiene, 1,3-pentadiene and 2,4-hexadiene. Suitable vinyl aromatics are, for example, styrene; ortho-, meta- and para-methylstyrene; commercial mixtures of "vinyltoluene"; para-tert.-butylstyrene; methoxystyrenes; chlorostyrenes; Divinylbenzene and vinylnaphthalene.
The resulting copolymers may contain from 99 to 20% by weight of diene units and from 1 to 80% by weight of vinylaromatic units. The resulting elastomers have any microstructure that is a function of the polymerization conditions used, especially the presence or absence of modifiers and / or randomizers, and the amount of modifiers and / or randomizers used. I can do it. The resulting elastomer can be, for example, a block, random, ordered or micro-ordered elastomer, can be prepared in a dispersion or solution, and can be further treated with coupling and / or starring or functionalizing agents. It can be coupled and / or starred or functionalized.
[0016]
Preference is given to polybutadienes, especially those having a 1,2-unit content of 4% to 80% or polybutadienes having a cis-1,4 content of more than 80%; polyisoprenes; butadiene-styrene Copolymers, in particular 5% to 50% by weight, especially 20% to 40% by weight, styrene content, 4% to 65% butadiene component 1,2-bond content and 20% to 80% trans-1 Butadiene-isoprene copolymers, especially an isoprene content of 5% to 90% by weight and a glass transition temperature of -40C to -80C ("Tg", ASTM standard D3418-82 Isoprene-styrene copolymers, especially those having a styrene content of 5% to 50% by weight and a Tg of -25 ° C to -50 ° C. In the case of butadiene-styrene-isoprene copolymers, suitable are, inter alia, 5% to 50% by weight, especially 10% to 40% by weight, styrene content, 15% to 60% by weight, especially 20% to 50% by weight. Isoprene content, 5% to 50% by weight, especially 20% to 40% by weight butadiene content, 4% to 85% butadiene component 1,2-unit content, 6% to 80% butadiene component trans Copolymers having a -1,4 unit content, 5% to 70% isoprene component 1,2- + 3,4-unit content and 10% to 50% isoprene component trans-1,4 unit content, Generally, any butadiene-styrene-isoprene copolymer having a Tg of -20C to -70C.
In short, it is particularly preferred that the diene elastomers of the composition according to the invention are made of polybutadienes (BR), polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures thereof. Is to choose from the group of unsaturated diene elastomer fistulas. Such copolymers more preferably consist of butadiene-styrene copolymers (SBR), butadiene-isoprene copolymer (BIR), isoprene-styrene copolymer (SIR) and isoprene-butadiene-styrene copolymer (SBIR). Selected from the group.
[0017]
The compositions according to the invention are intended, inter alia, for treads for new or used tires (in the case of recapping).
For passenger vehicle tires, the diene elastomer may be, for example, SBR (SBR prepared in emulsion ("ESBR") or SBR prepared in solution ("SSBR")), SBR / BR, SBR / NR (or SBR / IR), BR / NR (BR / IR), and blends (mixtures). In the case of SBR elastomers, inter alia, a styrene content of 20% to 30% by weight, a vinyl bond content of the butadiene fraction of 15% to 65%, a trans-1,4 bond content of 15% to 75% and -20% SBR with a Tg of between ℃ and -55 ° C is used. Such SBR copolymers, preferably prepared in solution (SSBR), are optionally used, preferably in a mixture with polybutadiene (BR) having more than 90% cis-1,4 bonds.
For utility vehicles, especially heavy vehicles, the diene elastomer is preferably an isoprene elastomer; "isoprene elastomer" is, as is known, an isoprene homopolymer or copolymer, in other words, natural rubber (NR), synthetic polyisoprene. It is to be understood that this means a diene elastomer selected from the group consisting of (IR) s, various isoprene copolymers and mixtures of these elastomers. Among the isoprene copolymers, among others, isobutene-isoprene copolymer (butyl rubber (IIR)), isoprene-styrene copolymer (SIR), isoprene-butadiene copolymer (BIR), or isoprene-butadiene-styrene copolymer (SBIR) No. The isoprene elastomer is preferably natural rubber or a synthetic polyisoprene of the cis-1,4 type; of these synthetic polyisoprenes, preferably more than 90%, more preferably more than 98% cis- Polyisoprene having a 1,4 bond content (mol%) is used. In such a tire for a practical vehicle, the diene elastomer may be entirely or partially constituted by another highly unsaturated elastomer such as an SBR elastomer.
According to another advantageous embodiment of the invention, especially when the invention is intended as a tire sidewall, the composition according to the invention comprises at least one essentially saturated diene elastomer, in particular at least one EPDM A copolymer may be included with or without using the copolymer, for example, as a mixture with one or more highly unsaturated diene elastomers described above.
The composition of the present invention may contain a single diene elastomer or a mixture of several diene elastomers, the one or more elastomers being any type of synthetic or non-elastomer polymers other than diene elastomers, For example, it may even be used with thermoplastic polymers.
[0018]
II-2 Reinforcing filler
The white or inorganic fillers used as reinforcing fillers may constitute all or only part of the entire reinforcing filler, in the latter case for example with carbon black.
Preferably, in the rubber composition according to the invention, the reinforcing inorganic filler is a large proportion of the total reinforcing filler, i.e. more than 50% by weight, more preferably more than 80% by weight of the total reinforcing filler. Also make up a lot.
In the present application, a "reinforcing inorganic filler" refers to a "white" filler, sometimes a "clear" filler, relative to carbon black, regardless of its color and origin (natural or synthetic). It is to be understood, as known, that it refers to inorganic or mineral fillers referred to. This inorganic filler, by itself, can reinforce a rubber composition intended for tire manufacture without any means other than an intermediate coupling agent, in other words, a normal tire-grade carbon black filler. It can replace the agent and its reinforcing function.
Preferably, the reinforcing inorganic filler is silica (SiO_Two) Or alumina (Al_TwoO_Three) Type of inorganic filler or a mixture of these two fillers.
[0019]
The silica used may be any reinforcing silica known to those skilled in the art, especially 450 m each.^Two/ g, preferably 30-400 m^TwoAny precipitated or fumed silica having a BET surface area and a specific CTAB surface area of / g. Highly dispersible precipitated silica (designated "HD") is particularly preferred when the present invention is used in the manufacture of tires having low rolling resistance; "highly disperse silica" disintegrates in an elastomeric matrix and It is understood as meaning any silica having a substantial ability to disperse, which ability can be observed by electron or light microscopy on thin sections by known methods. Non-limiting examples of such preferred highly dispersible silicas include silica Perkasil KS 430 from Akzo; silica BV3380 from Degussa; silicas Zeosil 1165 MP and 1115 MP from Rhodia; Silica Hi-Sil 2000; silicas from Huber, Zeopol 8741 or 8745; and treated precipitated silicas such as, for example, aluminium- "doped" silica, as described in US Pat.
Alumina for reinforcement which can be preferably used is 30 to 400 m as described in Patent Document 5.^Two/ g, more preferably 60-250 m^TwoHighly dispersible alumina having a BET surface area of / g and an average particle size of at most equal to 500 nm, more preferably at most equal to 200 nm. Non-limiting examples of such reinforcing aluminas are the aluminas "Baikalox" "A125", "CR125" and "D65CR" from Baikowski, among others.
[0020]
The physical state in which the reinforcing inorganic filler is present, whether in the form of powder, microbeads, granules or spheres, is not critical. Of course, "reinforcing inorganic fillers" is to be understood as meaning also various reinforcing inorganic fillers, especially mixtures of highly disperse silicas and / or aluminas as described above.
When the rubber composition of the present invention is used as a tread for a tire, the reinforcing inorganic filler to be used is preferably silica, particularly preferably 60 to 250 m.^Two/ g, more preferably 80-200 m^Two/ g BET surface area.
The reinforcing inorganic filler can also be used in a blend (mixture) with carbon black. Suitable carbon blacks are carbon blacks of the type HAF, ISAF and SAF commonly used in all carbon blacks, especially in tires, especially in treads for tires. Non-limiting examples of such carbon blacks include black N115, N134, N234, N339, N347 and N375.
Although the amount of carbon black present in the entire reinforcing filler can vary over a wide range, the amount of carbon black is preferably less than the amount of reinforcing inorganic filler present in the rubber composition of the present invention.
[0021]
In the compositions according to the invention, in particular in the treads containing such compositions, a small proportion of carbon black, preferably in the range of 2 to 20 phr, more preferably 5 to 15 phr, is added to the reinforcing inorganic filler. Is to be used with In these ranges, the coloring properties (black colorant) and UV resistance properties of carbon black are evaluated by the typical performance obtained with reinforcing inorganic fillers, namely low hysteresis (reduced rolling resistance) and wet, snowy. It has also been noted that there is the advantage that it can be obtained without further adversely affecting the high ground contact on icy ground.
The total amount of reinforcing filler (reinforcing inorganic filler + carbon black when used) is preferably from 10 to 200 phr, more preferably from 20 to 150 phr, the optimum amount of which depends on the intended use. This is because, for example, the expected reinforcement level in bicycle tires is higher than that required in tires that tend to move continuously at high speed, for example, tires for practical use such as motorcycle tires, passenger vehicle tires or heavy vehicles. Is also known to be very low.
In such treads for tires that can move at high speed, the amount of reinforcing inorganic filler, especially when it is silica, is preferably in the range of 30 to 140 phr, more preferably 50 to 120 phr.
As used herein, the BET specific surface area is described in “The Journal of the American Chemical Society”, vol. 60, page 309, February 1938 and corresponds to the French standard NF T 45-007 (November 1987). Measured by known methods according to the method of Brunauer, Emmett and Teller; CTAB specific surface area is the external surface area measured according to the same standard NFT 45-007.
Finally, those skilled in the art will recognize that, as fillers equivalent to the reinforcing inorganic fillers described in this section, reinforcing organic fillers, especially inorganic layers, for example, carbon black coated with silica (part of which is , Which requires the use of a coupling agent that provides a bond to the elastomer).
[0022]
II-3. Coupling agent ( Organosilicon compounds )
As mentioned above, (inorganic filler / diene elastomer) coupling agents carry at least two functional groups, referred to herein as "Y" and "X", while the Y group, For example, it may be grafted to the reinforcing inorganic filler by means of hydroxyl groups or hydrolysable groups, and on the other hand to diene elastomers by means of X groups, for example sulfur groups.
One essential feature of the polysilylated organosilicon compound used as a coupling agent in the composition according to the present invention is that the compound is attached to the elastomer by a sulfur group having a polythiosulfenamide function of the formula What can be grafted is:
(I) ≡ Si − A − S_x − N R¹ R^Two
Wherein A is a linear or branched divalent linking group that enables the polythiosulfenamide group to be linked to the first silicon atom of the organosilicon compound;
x is an integer or a fraction of 2 to 4;
R¹Is hydrogen, a monovalent hydrocarbon group or R^TwoShows;
R^TwoRepresents the following groups:
− B − Si ≡
B is a linear or branched divalent group;
Si represents the second silicon atom of the organosilicon compound).
Recall that an "organosilicon" ("organosilicon") compound is by definition to be understood to be an organic compound containing at least one carbon-silicon bond. The compounds of the above formula (I) carry at least two different silicon atoms (at least one attached to group A, at least one other attached to group B) and are therefore polysilylated organosilicon compounds. It should be understood that it belongs to the category. Furthermore, R¹Is R^TwoIt should also be noted that, when (in its general formula), the compound of formula (I) carries at least three different silicon atoms.
[0023]
In the above formula (I), the number x is an integer equal to 2, 3 or 4, preferably equal to 2 or 3, if the synthetic route of the compound can result in only a single type of polysulphide group .
However, one skilled in the art will recognize that this number can be a normal fraction if the synthetic route results in a mixture of polysulphide groups each having a different number of sulfur groups; in such cases the synthesized polythiosulfur The phenamide group is actually a disulfide S centered on the average (mole) of 2 to 4, more preferably 2 to 3, "x" numbers (fractions)_TwoProducing with a distribution of polysulfides from to heavier polysulfides could be easier.
The divalent group A is preferably a saturated or unsaturated aliphatic hydrocarbon group; a saturated, unsaturated and / or aromatic, monocyclic or polycyclic carbocyclic group; and a saturated or unsaturated It is selected from groups having an aliphatic hydrocarbon component and a carbocyclic component as described above.
The bonding group A preferably contains 1 to 18 carbon atoms, and more preferably represents an alkylene chain, a saturated cycloalkylene group, an arylene group, or a divalent group consisting of a combination of at least two of these groups.
R¹The monovalent hydrocarbon group represented by may be an aliphatic straight or branched group, or a carbocyclic, especially an aromatic group; it may be substituted or unsubstituted, saturated or unsaturated.
In the case of an aliphatic hydrocarbon group, this group contains, inter alia, 1 to 25 carbon atoms, more preferably 1 to 12 carbon atoms.
Examples of the saturated aliphatic hydrocarbon group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, 2-methylbutyl, 1-ethylpropyl, hexyl, isohexyl, neohexyl, and 1-hexyl. Methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 1,3-dimethylbutyl, 2-ethylbutyl, 1-methyl-1-ethylpropyl, heptyl, 1-methylhexyl, 1-propylbutyl, 4,4 -Alkyl groups such as -dimethylpentyl, octyl, 1-methylheptyl, 2-ethylhexyl, 5,5-dimethylhexyl, nonyl, decyl, 1-methylnonyl, 3,7-dimethyloctyl and 7,7-dimethyloctyl be able to.
[0024]
Unsaturated aliphatic hydrocarbon groups that can be used include one or more sites of unsaturation, preferably one, two or three, unsaturated type of ethylene type (double bond) and / or acetylene type (triple bond). Including the site. Examples of these are alkenyl or alkynyl groups derived from the abovementioned alkyl groups by removing two or more hydrogen atoms. Preferably, the unsaturated aliphatic hydrocarbon group contains one site of unsaturation.
“Carbocyclic group” refers to an optionally substituted monocyclic or polycyclic group, preferably C_Three~ C₁₈It should be understood to mean a group. Advantageously, the carbocyclic group is a C, preferably monocyclic, bicyclic or tricyclic_Three~ C₅₀Group. When a carbocyclic group contains more than one cyclic core (as in a polycyclic carbocycle), the cyclic cores are fused two by two. The two condensed cores can be of the ortho-condensed or peri-condensed type.
The carbocyclic group may contain a saturated component and / or an aromatic component and / or an unsaturated component unless otherwise specified.
An example of a saturated carbocyclic group is a cycloalkyl group. The cycloalkyl group is preferably C_Three~ C₁₈Group, more preferably C_Five~ C_TenGroup. In particular, mention may be made of cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl or norbornyl.
Any unsaturated moiety of the unsaturated carbocycle or carbocyclic type has one or more, preferably one, two or three, ethylenically unsaturated sites. The carbocycle or component advantageously contains 6 to 50 carbon atoms, more preferably 6 to 20, for example 6 to 18 carbon atoms.
Examples of unsaturated carbocycles include C₆~ C_TenIt is a cycloalkyl group. The aromatic carbocyclic group is C₆~ C₁₈Aryl groups are especially phenyl, naphthyl, anthryl and phenanthryl.
The group having both the aliphatic hydrocarbon component and the carbocyclic component as described above is, for example, an arylalkyl group such as benzyl or an alkylaryl group such as tolyl.
The substituents on the aliphatic hydrocarbon group or component and the carbocyclic group or component are, for example, an alkoxy group in which the alkyl component is preferably as described above.
R¹Contains 1 to 25 carbon atoms. According to one particularly preferred embodiment, R¹Is hydrogen, straight or branched C₁~ C₈Alkyl, C_Five~ C_TenCycloalkyl, C₆~ C₁₈Aryl, (C₆~ C₁₈) Aryl- (C₁~ C₈) Alkyl and R^TwoSelected from the group consisting of: More preferably, R¹Is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, hexyl, benzyl, cyclohexyl, phenyl, benzyl and R^TwoSelected from the group consisting of:
[0025]
The divalent linking groups A and B, which may be the same or different and preferably contain 1 to 18 carbon atoms, are more preferably C₁~ C₁₈Alkylene (hereinafter referred to as “Z”), and C₆~ C₁₂Selected from among arylenes; these groups may be substituted or interrupted by one or more heteroatoms selected amongst S, O and N, among others.
That is, according to a particularly preferred embodiment of the present invention, the sulfur group of formula (I) has the specific formula (II) (where A = B = Z) or the formula (III) (where A = Z and B = − S_y − Z −) is satisfied:
(II) ≡ Si − Z − S_x − N R¹ − Z − Si ≡,
(III) ≡ Si − Z − S_x − N R¹ − S_y − Z − Si ≡
Wherein the groups Z may be the same or different and C₁~ C₈Represents alkylene; y can be the same or different from x and is an integer or fraction of 2 to 4).
In these formulas (II) and (III), Z is more preferably C₁~ C_FourIndicate an alkylene chain, especially methylene, ethylene or propylene, more preferably propylene.
In the above formulas (I), (II) and (III), R^TwoPreferably denotes the following groups:
− B − Si R^Three _(3-a) (OR^Four)_a
(Where R^ThreeRepresents a monovalent hydrocarbon group;
R^FourIs hydrogen, or R^ThreeRepresents the same or different monovalent hydrocarbon group as
a is an integer equal to 1, 2 or 3;
In particular, B = Z for the above specific formula (II) or B = −S for the above specific formula (III)_y −Z−).
[0026]
Group R^ThreeAnd R^FourMay be the same or different and are, inter alia, saturated or unsaturated aliphatic hydrocarbon groups; saturated, unsaturated and / or aromatic monocyclic or polycyclic carbocyclic groups; and saturated or unsaturated An aliphatic hydrocarbon component and a hydrocarbon group selected from groups having a carbocyclic component as described above, preferably containing 1 to 18 carbon atoms, and these various groups may be optionally substituted. Or do not replace.
Group R^ThreeMay be the same or different when plural, and preferably represents alkyl, cycloalkyl or aryl. These groups are more preferably C₁~ C₈Alkyl, C_Five~ C_TenIt is selected from the group consisting of cycloalkyl (especially cyclohexyl) and phenyl. More preferably, R^ThreeIs C₁~ C₆It is selected from the group consisting of alkyl (among others, methyl, ethyl, propyl and isopropyl).
Group R^FourMay be the same or different when plural, and preferably represents alkyl, cycloalkyl, acyl or aryl. These groups are more preferably optionally halogenated and / or optionally one or more (C_Two~ C₈C) alkoxy substituted₁~ C₈Alkyl; optionally halogenated and / or optionally one or more (C_Two~ C₈C) alkoxy substituted_Two~ C₉Acyl; C_Five~ C_TenCycloalkyl and C₆~ C₁₈It is selected from the group consisting of aryl. More preferably, R^FourMay be replaced by one or more (C_Two~ C₈C) substituted with alkoxy (especially methoxy, ethoxy, propoxy, isopropoxy)₁~ C₈Alkyl (among others, methyl, ethyl, n-propyl, isopropyl, n-butyl, β-chloropropyl, β-chloroethyl); C_Five~ C_TenIt is selected from the group consisting of cycloalkyl and phenyl.
According to the best perceived embodiment, the group R^ThreeAnd R^FourCan be the same or different and together C₁~ C_FourSelected among alkyl, especially methyl and ethyl (if a ≠ 3).
[0027]
One skilled in the art would be able to adapt the nature of the Y functionality to the particular organosilicon compound onto which the polythiosulfenamide group is grafted, via the linking group A. This functional group Y can be different, for example a hydroxyl or hydrolysable group, according to the type of the organosilicon compound.
Without being limited to this embodiment, the present organosilicon compound is preferably a silane compound carrying an (OR) group fixed to one or more (up to three) silicon atoms as a Y functional group, wherein R is Indicates hydrogen or a linear or branched monovalent hydrocarbon group (particularly, alkyl).
Thus, particularly suitable organosilicon compounds in the present invention may be polysilylated polythiosulfenamidosilanes of the general formula:
(IV) (R⁶O)_b R^Five _(3-b) Si − A − S_x − N R¹ − B − Si R^Three _(3-a) (OR^Four)_a
(Where R^FiveRepresents a monovalent hydrocarbon group;
R⁶Is hydrogen, or R^FiveRepresents a monovalent hydrocarbon group which may be the same as or different from
b is an integer equal to 1, 2 or 3;
R^Five, R⁶And b are each R^Three, R^FourAnd may be the same or different from a).
In the above formula (IV), R^Five, R⁶And b are each R^Three, R^FourAnd has the generally preferred meanings described above for a. Above all, R^FiveIs more preferably C₁~ C₈Alkyl, C_Five~ C_TenSelected from the group consisting of cycloalkyl and phenyl; more preferably, R⁶Is C₁~ C₆Alkyl, C_Two~ C₆Alkoxyalkyl, C_Five~ C₈It is selected from the group consisting of cycloalkyl and phenyl.
According to the best perceived embodiment, R^FiveAnd R⁶Can be the same or different and C₁~ C₆Alkyl, more preferably C₁~ C_FourSelected from alkyl.
Those skilled in the art will recognize that the organosilicon compound according to formula (IV) can be converted to a polythiosulfenamide functional group of formula (I) [-S_x − N R¹ R^TwoThe first "Y" functional group [1 to 3 (OR fixed to the first silicon atom) bonded to the "X" functional group⁶)_bThe first is represented by the group consisting of at least one second “Y” functional group [1-3 (OR attached to the second silicon atom)^Four)_aIt can be easily understood that it has the advantageous additional feature of including
[0028]
Further preferred organosilicon compounds that can be used in the compositions of the present invention include, inter alia, polysilylated polythiosulfenamide silanes of the formula (IV) corresponding to one of the following specific formulas:
(V) (R⁶O)_b R^Five _(3-b) Si − Z − S_x − N R¹ − Z − Si R^Three _(3-a) (OR^Four)_aOr (VI) (R⁶O)_b R^Five _(3-b) Si − Z − S_x − N R¹ − S_y − Z − Si R^Three _(3-a) (OR^Four)_a
Wherein the groups Z can be the same or different, especially C₁~ C_FourRepresents an alkylene; a group R^Three, R^Four, R^FiveAnd R⁶Is especially C₁~ C_ThreeDenote alkyl; x and y have the definitions given above), and more particularly, dithiosulfenamidosilanes where x is equal to 2 and y where applicable is also equal to 2.
In these formulas (V) and (VI), Z is more preferably C₁~ C_FourRepresents an alkylene chain, especially methylene, ethylene or propylene, more preferably propylene;^Three, R^Four, R^FiveAnd R⁶Can be the same or different, more preferably C₁~ C_ThreeDenotes alkyl, especially methyl or ethyl.
Among the organosilicon compounds of the formula (V), for example,¹May be selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, hexyl, benzyl, cyclohexyl and phenyl:
N- (3'-trimethoxysilylpropyldithio) -3-triethoxysilylpropylamine (Formula V-1):
Embedded image

N- (3'-triethoxysilylpropyldithio) -3-triethoxysilylpropylamine (Formula V-2):
Embedded image

N-methyl-N- (3′-triethoxysilylpropyldithio) -3-trimethoxysilylpropylamine of the formula (V-3) (Et = ethyl; Me = methyl):
Embedded image

[0029]
According to a particularly preferred embodiment of the invention, the polysilylated polythiosulfenamidosilane is of the symmetric type (x = y), i.e. on either side of the N atom as shown in formula (VI) above. Are silanes containing the same number (2, 3 or 4) of S atoms.
In this formula (VI), on the other hand, R^Five, R⁶And b are each R^Three, R^FourIn a more specific case where silane is identical to and a, while the two bonds Z are identical, strictly symmetrical forms have the following particularly preferred formula:
(VII) [(R^FourO)_a R^Three _(3-a) Si − Z − S_x −]_Two N R¹
In the formula (VII), more preferably, R¹Is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, hexyl, benzyl, cyclohexyl and phenyl; Z is C₁~ C_FourRepresents an alkylene chain, more preferably propylene;^ThreeAnd R^FourIs R^ThreeMay be the same or different when present (a ≠ 3), more preferably C₁~ C_ThreeRepresents alkyl, especially methyl or ethyl; x is more preferably equal to 2).
Examples of organosilicon compounds having the structure of formula (VII) wherein x = 2 include, for example, the following compounds:
N, N-bis (3-trimethoxysilylpropyldithio) cyclohexylamine of the formula (VII-1):
Embedded image

N, N-bis (3-triethoxysilylpropyldithio) cyclohexylamine of the formula (VII-2):
Embedded image

N, N-bis (3-trimethoxysilylpropyldithio) -3-triethoxysilylpropylamine of the formula (VII-3):
Embedded image

[0030]
The above-mentioned polyfunctional coupling agents carrying polythiosulfenamide groups have shown very good reactivity towards diene elastomers used in rubber compositions for tires, such as silica and silica. It has been found that it is sufficiently effective by itself in coupling with reinforcing inorganic fillers. Without being limited to this, the polyfunctional coupling agent advantageously constitutes the sole coupling agent present in the rubber composition of the present invention.
In order to provide tolerance in the specific surface area and density of the reinforcing inorganic filler used and the molar mass of the specific coupling agent to be used, the reinforcing inorganic filler must be used for each reinforcing inorganic filler used. It is preferred to determine the optimal amount of coupling agent in moles per square meter of agent; this optimal amount is determined by the following known equation: mass ratio [coupling agent / reinforcing inorganic filler], filling Calculated from the BET surface area of the agent and the molar mass of the coupling agent (hereinafter referred to as M):
(Moles / m^TwoInorganic filler) = [coupling agent / inorganic filler] (1 / BET) (1 / M)
That is, preferably, the amount of coupling agent used in the composition according to the invention is determined by the amount of reinforcing inorganic filler^TwoPer 10^-7~Ten^-FiveIs a mole. More preferably, the amount of coupling agent is 5 x 10 per square meter of total inorganic filler^-7~ 5 x 10^-6Is a mole.
[0031]
In view of the amounts expressed above, in general, the content of coupling agent will preferably be greater than 1 phr, more preferably 2 to 20 phr. Below the minimum amount indicated, the effective risk is inadequate, whereas above the recommended maximum amount, no further improvement in coupling is generally observed and the cost of the composition increases; For reasons, this coupling agent content is more preferably between 3 and 12 phr.
One skilled in the art will appreciate that the coupling agent content depends on the intended use, for example, the tire component for which the composition of the present invention is intended, the nature of the diene elastomer, the amount of reinforcing inorganic filler used and the organosilicon. It can be adjusted according to the nature of the compound.
Of course, in order to save the cost of the rubber composition, it is preferred to use as little as possible, i.e. the amount which is justified for a sufficient coupling between the diene elastomer and the reinforcing inorganic filler. By virtue of its effectiveness, it is possible in many cases to use the coupling agents in preferred amounts representing from 0.5% to 20% by weight, based on the amount of reinforcing inorganic filler; less than 15%, especially 10%. % Is more preferred.
Finally, the aforementioned organosilicon compounds were previously grafted onto the reinforcing inorganic filler (via the "Y" functional group), and then the "pre-coupled" free radicals "X" Note that the "functional group can be attached to the diene elastomer.
[0032]
II-4. Coupling agent ( Organosilicon compounds ) Synthesis of
For example, an organosilicon compound as described above can be prepared according to the following preferred synthetic route (methods designated as A, B or C).
A) Method" A "
Polysilylated organosilicon compound compounds of the general formula (IV) (including certain formulas (V), (VI) and (VII)) wherein X = 2 (organosilicon compounds having a dithiosulfenamide functionality) The following formula:
(VIII) (R⁶O)_b R^Five _(3-b) Si − A − S − S − Hal
(Where A, R^Five, R⁶And b are as defined above; Hal is halogen (bromine, chlorine, fluorine or iodine, preferably chlorine)
With the following formula:
(IX) H N R¹ R^Two
(Where R¹And R^TwoIs as defined above)
By reacting the compound with a suitable amine, in the presence of a base, preferably an organic base.
Suitable bases are, for example, N-methylmorpholine, triethylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4- (1-pyrrolidinyl) pyridine, picoline, 4- (N, N-dimethylamino ) Pyridine, 2,6-di-tert-butyl-4-methylpyridine, quinoline, N, N-dimethylaniline, N, N-diethylaniline, 1,8-diazabicyclo [5.4.0] -undec-7-ene (DBU), 1,5-diazabicyclo [4.3.0] -non-5-ene (DBN) and 1,4-diazabicyclo [2.2.2] -octane (DABCO or triethylenediamine).
[0033]
The reaction is preferably carried out in a polar aprotic solvent such as an ether, for example diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, dimethoxyethane or diethylene glycol dimethyl ether. Diethylene ether is preferred.
The reaction temperature is a function of the reactivity of the molecules present and the power of the base used. This temperature generally varies from -78 ° C to ambient temperature (15-25 ° C). Advantageously, temperatures between -78 ° C and -50 ° C are suitable. Thereafter, the medium is preferably returned to ambient temperature.
When amine (IX) is a secondary amine (R¹Is other than H), the reaction is stoichiometric; in this case, the molar ratio of amine (IX) to halogenated disulfide (VIII) is chosen to be 1-2, and better still 1-1.5.
When amine (IX) is a primary amine (R¹Indicates H), the amount of which depends on the nature of the desired reaction product. R¹In order to obtain an organosilicon compound of the general formula (IV) wherein H represents H, the amine (IX) is in excess in the reaction medium. The molar ratio (IX) / (VIII) generally varies between 1 and 3, and this ratio is generally closest to 1, for example chosen between 1 and 1.2.
To obtain a particular organosilicon compound of formula (VII), the molar ratio of product (VIII) to amine (IX) is chosen to be 2 or more. This molar ratio (VIII) / (IX) is advantageously between 2 and 2.3. The amount of base used in this reaction can be readily determined by those skilled in the art, and the base has a role in capturing the released hydrohalic acid. The molar ratio of base to compound of formula (VIII) is 1 or more, for example 1-3.
[0034]
B) Method" B "
Polysilylated organosilicon compounds of the general formula (IV), including specific formulas (V)-(VII), wherein X = 2, have the following formula:
(X) (R⁶O)_b R^Five _(3-b) Si − A − S − S − J
(Where A, R^Five, R⁶And b are as defined above; J represents an optionally substituted succinimide or phthalimide group)
By reacting the above-mentioned disulfide with the above-mentioned amine (IX) in the presence of a base, preferably an organic base. Succinimide and phthalimide substituents are organic substituents that are compatible with the reaction used, ie, are unreactive under the operating conditions used. Bases which can be used are the bases mentioned above in method A.
Advantageously, the reaction is carried out in an aprotic polar solvent, preferably an aliphatic halogenated hydrocarbon (such as methylene chloride or carbon tetrachloride) or optionally halogenated aromatic hydrocarbon (optionally halogenated). Benzene or toluene). Preferably, the solvent is CCl_FourIt is. The reaction temperature is preferably from 10C to 100C, more preferably from 10C to 50C. The respective amounts of the compounds (IX) and (X) used depend exactly on the type of organosilicon compound desired, as in the case described above (Method A).
Thus, see method A for determining the molar amounts of (IX), (X) and the base to be reacted.
[0035]
C) Method" C "
Polysilylated organosilicon compounds of the general formula (IV), including specific formulas (V)-(VII), wherein X = 2, have the following formula:
(XI) J − S − N R¹ R^Two
(Where R¹, R^TwoAnd J are as defined above)
With the following formula:
(XII) (R⁶O)_b R^Five _(3-b) Si −^A − SH
(Where A, R^Five, R⁶And b are as defined above)
It can also be obtained by reacting with a thiol in the presence of a base (the base is preferably as described above).
In this reaction, the reaction temperature advantageously varies between 10 and 40C, more preferably between 15 and 30C, for example between 18 and 25C. The reaction of compound (XII) on compound (XI) is generally carried out in a polar aprotic solvent as described in the case of method B. Preferably, the solvent is benzene or toluene. The reaction is a stoichiometric reaction. However, it is preferred to work in the presence of a slight excess of compound (XI). That is, the molar ratio of (XI) to (XII) is generally from 1 to 1.5, and more preferably from 1 to 1.3.
This variant C is, inter alia, R¹Is other than a hydrogen atom in the preparation of the organosilicon compound of the general formula (IV) (including the specific formulas (V) to (VII)).
The compound of the formula (VIII) is obtained by using sulfur dichloride (SCl_Two) On a suitable mercaptosilane of formula (XII) as described above in the presence of an organic base, preferably in the presence of triethylamine. The reaction is carried out, for example, in ether at a temperature between -78 ° C and -50 ° C. Organic bases and ethers are generally as described above.
Amines (IX) are commercially available amines or can be easily prepared from commercial products.
[0036]
Compounds of formula (X) can be readily prepared by reacting a thiol of formula (XII) as described above on a halide of the following formula:
(XIII) J − S − Hal
(Wherein J and Hal are as defined above).
The reaction is preferably carried out in the presence of a base, especially an organic base, at a temperature of from 10 ° C to 50 ° C, for example from 15 ° C to 30 ° C, especially from 18 ° C to 25 ° C, at the polar non-polarity described generally in Method B. Performed in a protic solvent. Preferably, the solvent is carbon tetrachloride, the base is triethylamine, and the temperature is ambient. The reaction is stoichiometric, but nevertheless preferably operates in the absence of thiol (VII). That is, the molar ratio of compound (XIII) to compound (XII) is advantageously from 1 to 1.5, and better still from 1 to 1.3.
Compounds of formula (XI) are readily obtained by reacting an amine (IX) on a halide of formula (XIII) in the presence of an organic base. The reaction is preferably carried out in a solvent of the halogenated hydrocarbon type (especially carbon tetrachloride), generally at a temperature of 10 ° C to 50 ° C, preferably 15 ° C to 30 ° C, for example 18 ° C to 25 ° C (ambient temperature). ). As the organic base, any of the above-mentioned bases, for example, triethylamine is selected. In a variant, reagent (IX) can be used as base. In this case, at least two equivalents of the amine (IX) are used for one equivalent of the halide (XIII).
Compounds of formula (XII) are commercially available compounds or can be readily prepared from commercially available compounds.
Formula 1 below illustrates a synthetic route for compound (XIII):
Embedded image

Wherein J and Hal are as defined above; M represents an alkali metal, preferably Na or K.
Commercially available compound (XIV) is converted to a C, such as methanol or ethanol, by the action of a suitable inorganic base of the alkali metal hydroxide type, i.e., M-OH, where M is an alkali metal.₁~ C_FourConvert to alkali metal salt in lower alcohol. The reaction generally occurs at a temperature between 15C and 25C. The resulting salt of formula (XV) is represented by S_TwoCl_TwoTo give compound (XVI). Advantageous reaction conditions in this reaction are polar aprotic solvents of the halogenated aliphatic hydrocarbon type (CH_TwoCl_Two, CCl_Four) And a temperature of -20 ° C to 10 ° C. Then, the expected compound (XIII) is obtained by the action of Hal-Hal on the compound (XVI). In this latter step, the operation is preferably carried out in a polar aprotic solvent of the halogenated aliphatic hydrocarbon type (such as chloroform or dichloromethane) at a temperature from 15 ° C. to the reflux temperature of the solvent, preferably Is between 40 ° C and 80 ° C, for example between 50 ° C and 70 ° C. According to one preferred embodiment, Hal is chlorine, in which case Hal-Hal is introduced into the reaction medium in gaseous form.
[0037]
D) Method" D "
A polysilylated organosilicon compound of the general formula (IV) (including certain formulas (V) to (VII)) wherein X = 3 can be obtained by combining the following steps:
(1) The thiol of the formula (XII) is converted to S_Two(Hal)_Two (Wherein Hal represents a halogen atom, preferably chlorine) in the presence of a base, preferably an organic base, to give:
(XVII) (R⁶O)_b R^Five _(3-b) Si − A − S − S − S − Hal
The reaction is carried out, for example, in ether at a temperature between -78 ° C and -50 ° C. The organic bases and ethers are generally as described in Method A.
(2) reacting compound (XVII) on a suitable amine of formula (IX) in the presence of a base, preferably an organic base; for further details, reference may be made to the procedure described above in the performance of Method A.
E) Method" E "
A polysilylated organosilicon compound of the general formula (IV) (including certain formulas (V) to (VII)) wherein X = 4 can be obtained by combining the following steps:
(1) reacting a halogenated disulfide of the formula (VIII) or a halogenated trisulfide of the formula (XVII) with a required amount of elemental sulfur (in the case of the compound (VIII), by supplying 2 sulfur atoms, the compound (XVII) In the presence of one sulfur atom) and operating at a temperature of 70 ° C. to 170 ° C., optionally in the presence of an aromatic solvent, to give compounds of the following formula:
(XVIII) (R⁶O)_b R^Five _(3-b) Si − A − S − S − S − S − Hal
(2) reacting compound (XVIII) on a suitable amine of formula (IX) in the presence of a base, preferably an organic base; for further details, reference may be made to the operating procedures described above in the practice of Method A.
[0038]
II-5. Various additives
Needless to say, the rubber composition according to the present invention includes, for example, plasticizers; extender oils; protective agents such as ozone-resistant waxes, chemical ozone-resistant agents, antioxidants; anti-fatigue agents; Coupling activators as described in Nos. 10 and 11; Reinforcing resins as described in U.S. Pat. No. 6,047,098; Any of sulfur-based or sulfur and / or peroxide and / or bismaleimide donor systems It may also contain all or the same additives normally used in diene rubber compositions intended for the manufacture of tires, such as crosslinking systems; vulcanization accelerators; vulcanization activators and the like. In addition, if necessary, ordinary white fillers having poor or non-reinforcing properties, for example, particles of clay, bentonite, talc, chalk or kaolin, may be used together with the above-mentioned reinforcing inorganic fillers.
The rubber composition according to the present invention, in addition to the organosilicon compound described above, for coating a reinforcing inorganic filler, for example, a drug containing one functional group Y, or to improve the processing ability in an uncured state As is known, a more general processing aid for further reducing the viscosity of the rubber composition for improving the dispersibility of the inorganic filler in the rubber matrix may be contained. These agents are, for example, alkylalkoxysilanes, in particular 1-octyltriethoxysilane, for example marketed by the company Degussa-Huls under the trade name Dynasylan Octeo or 1-, marketed by the company Degussa-Huls under the trade name Si216. Alkyltriethoxysilanes such as hexadecyltriethoxysilane; polyols; polyethers (eg, polyethylene glycols); primary, secondary or tertiary amines (eg, trialkanolamines); Hydroxylated or hydrolysable polyorganosiloxanes, for example α, ω-dihydroxypolyorganosiloxanes (especially α, ω-dihydroxypolydimethylsiloxanes).
[0039]
II-6. Preparation of rubber composition
The compositions of the present invention are prepared in two successive production stages well known to those skilled in the art, namely at a maximum temperature (T_maxA first step (sometimes referred to as a "non-production" step) of thermomechanical processing or kneading at elevated temperatures up to and including a lower temperature, typically below 120C, for example between 60C and 100C. Manufactured in a suitable mixer using a second stage (sometimes referred to as a "production" stage) that incorporates a crosslinking or vulcanization system in this finishing stage; Are described in, for example, the above-mentioned Patent Documents 1, 3, 5, 7, 10, 11, and 12.
The method for producing the composition according to the present invention comprises mixing at least the reinforcing inorganic filler and the organosilicon compound into the diene elastomer by kneading in the first so-called non-production stage, that is, at least each of these base components. Is introduced into a mixer and thermomechanically kneaded in one or more steps until a maximum temperature of 110 ° C to 190 ° C, preferably 130 ° C to 180 ° C is reached.
[0040]
For example, the first (non-production) stage is carried out in a single thermo-mechanical process, during which the first stage removes all the necessary base components (diene elastomer, reinforcing inorganic filler and organosilicon compound). Then, in a second stage, after kneading, for example for 1-2 minutes, any additional coatings or processing agents except for the vulcanization system and various other additives are added to a suitable, such as a conventional internal mixer. Introduce into the mixer; if the apparent density of the reinforcing inorganic filler is low (generally silica), it may be advantageous to split the introduction into two or more parts. The second stage of thermo-mechanical processing involves subjecting the composition to a supplemental heat treatment in this internal mixer after the mixture has been dropped and after intermediate cooling (preferably a cooling temperature of less than 100 ° C.). For the purpose, inter alia, it may be added to further improve the dispersion of the reinforcing inorganic filler and its coupling agent in the elastomer matrix. The total kneading time in this non-production stage is preferably between 2 and 10 minutes.
After cooling the mixture thus obtained, the vulcanization system is mixed in at low temperature, generally in an open mixer such as an open mill; afterwards the whole mixture is mixed for a few minutes, for example 5 to 15 minutes. Mix (production stage).
The final composition thus obtained is then calendered, for example, into the form of a film or sheet, or extruded, for example, into treads, crown reinforcement plies, side walls, carcass reinforcement plies, beads, protectors Manufacture rubber shaped elements for use in the manufacture of semi-finished products such as inner tubes or hermetic inner rubber for tubeless tires.
[0041]
In short, the method according to the invention for the production of an elastomer composition that can be used in the production of semi-finished products for tires comprises the following steps:
-In a mixer, in a diene elastomer, at least:
-Inorganic filler for reinforcement,
-An organosilicon compound which is at least difunctional and can be grafted onto the elastomer by means of sulfur groups, as (inorganic filler / diene elastomer) coupling agent,
Mixing step;
Thermomechanically kneading the whole mixture in one or more steps until a maximum temperature of 110 ° C to 190 ° C is reached;
Cooling the whole mixture to a temperature below 100 ° C .;
・ Next, a step of mixing a vulcanization system;
Kneading the entire mixture until a maximum temperature of less than 120 ° C. is reached;
Wherein the sulfur group is a group having a polythiosulfenamide functional group of the formula (I).
Vulcanization (i.e., curing) is carried out in a known manner, generally at a temperature of from 130C to 200C, preferably under pressure, especially at the curing temperature, the vulcanization system used and the vulcanization rate of the composition. It is carried out for a sufficient time, which can vary depending on, for example, 5 to 90 minutes.
Suitable vulcanization systems are preferably based on sulfur and primary vulcanization accelerators, especially those of the sulfenamide type. Various known secondary accelerators or additives such as zinc oxide, stearic acid, guanidine derivatives (particularly diphenylguanidine) or the like may be added to the cross-linking system during the first non-production stage and / or during the production stage. Add the sulfur activator and mix. Sulfur is preferably used in an amount of 0.5 to 10 phr, more preferably 0.5 to 5.0 phr, for example 0.5 to 3.0 phr, when applying the present invention to a tire tread. Primary vulcanization accelerators are preferably used in amounts of 0.5 to 10 phr, more preferably 0.5 to 5.0 phr, especially when the invention is applied to tire treads.
The present invention relates to the above rubber compositions in both the "uncured" state (i.e., before curing) and the "cured" or vulcanized state (i.e., after crosslinking or vulcanization). The composition according to the present invention can be used alone or in a blend (ie, a mixture) with any other rubber composition that can be used in tire manufacturing.
BEST MODE FOR CARRYING OUT THE INVENTION
[0042]
III. Embodiment of the present invention
III-1. Synthesis of coupling agent
Coupling agents that can be preferably used in the composition of the present invention are dithiosulfenamidosilanes, more preferably of formulas (V-1) to (V-3) and (VII-1) to (VII-3). These are alkoxysilanes corresponding to dithiosulfenamidosilanes, and their synthesis is described below by way of non-limiting examples.
Melting points (Pf), expressed in degrees Celsius (° C), are measured by protrusions on a previously calibrated (ΔT = ± 2 ° C) KOFFLER device. Boiling point (Eb_pressure) Are in millibars (mbar). 250 MHz proton (¹H-NMR) and carbon (¹³(C-NMR) spectra are recorded on a BRUCKER AC 250 spectrometer. Chemical shifts (δc and δh) are determined by_Three) In parts per million by mass (ppm). Coupling constant J is expressed in Hz. The following abbreviations are used: s, singlet; bs, broad singlet; d, doublet; t, triplet; q, quadruple; m, multiplet.
All operations on the above alkoxysilanes are performed in an inert atmosphere and under anhydrous conditions.
Embodiment 1
[0043]
In this first test, N- (3'-trimethoxysilylpropyldithio) -3-propyltriethoxysilyl-propylamine is synthesized.
A solution of 100 mmol (ie 10.3 g) of sulfur dichloride in 400 ml of anhydrous diethyl ether is cooled to -78 ° C in a 2 liter three-necked flask under an argon atmosphere. With mechanical stirring, a mixture of 3-mercaptopropyltrimethoxysilane (100 mmol) and triethylamine (100 mmol, ie 10.2 g) in 150 ml of anhydrous diethyl ether is added dropwise over 1 hour. The reaction medium is stirred at this temperature for 1 hour, then a mixture of 3- (triethoxysilyl) -propylamine (110 mmol) and triethylamine (100 mmol, ie 10.2 g) in 100 ml of anhydrous diethyl ether is added dropwise. In one hour. The reaction medium is returned to room temperature, after which the triethylamine chlorohydrate is filtered off and the concentration is carried out under reduced pressure. Distillation under reduced pressure allows removal of traces of unreacted reagent.
NMR analysis confirms that the final compound thus obtained (appearance of yellow oil, yield 75%) corresponds to the above-mentioned specific formula (V-1):
Embedded image

・¹H NMR (CDCl_Three) δ_H
0.62 (t, 2H, Si-CH_Two); 0.74 (t, 2H, Si-CH_Two); 1.21 (t, 9H, CH_Three-CH_Two-O);
1.69 (m, 2H, CH_Two); 1.82 (m, 2H, CH_Two); 2.88 (t, 2H, SCH_Two);
3.07 (t, 2H, NCH_Two); 3.55 (s, 9H, O-CH_Three); 3.81 (q, 6H, -OCH_Two).
・¹³C NMR (CDCl_Three) δ_C
6.2 (Si-CH_Two); 9.7 (Si-CH_Two); 18.4 (CH_Three-CH_Two); 20.9 (CH_Two); 23.8 (CH_Two);
44.0 (S-CH_Two); 50.6 (-OCH_Three); 54.9 (N-CH_Two); 58.5 (-OCH_Two)
That is, an organooxysilane-dithiosulfenamide of general formula (V) was prepared as follows:
-R¹ = H;
-R^Two = − Z − Si (OR^Four)_Three;
‐ Z = (CH_Two)_Three (propylene);
-R^Four = Ethyl; R⁶ = Methyl;
‐ A = b = 3
Embodiment 2
[0044]
Perform the same procedure, but by substituting the 3-mercaptopropyltrimethoxysilane with 3-mercaptopropyltriethoxysilane, as evidenced by NMR analysis, the N- of the specific formula (V-2) described above. (3′-Triethoxysilylpropyldithio) -3-triethoxysilylpropylamine (yellow oily appearance, 86% yield) is obtained:
Embedded image

・¹H NMR (CDCl_Three) δ_H
0.61 (t, 2H, Si-CH_Two); 0.72 (t, 2H, Si-CH_Two); 1.21 (m, 18H, CH_Three-CH_Two-O);
1.69 (2, 2H, CH_Two); 1.83 (m, 2H, CH_Two); 2.89 (t, 2H, S-CH_Two);
3.05 (t, 2H, N-CH_Two); 3.81 (m, 12H, -OCH_Two).
・¹³C NMR (CDCl_Three) δ_C
6.2 (Si-CH_Two); 9.7 (Si-CH_Two); 18.3 (CH_Three-CH_Two); 18.4 (CH_Three-CH_Two);
20.9 (CH_Two); 23.8 (CH_Two); 44.0 (S-CH_Two); 54.9 (N-CH_Two); 58.5 (-OCH_Two);
58.6 (-OCH_Two)
Embodiment 3
[0045]
Performing the procedure of Example 1, but substituting the above 3- (triethoxysilyl) -propylamine with cyclohexylamine and using 55 mmol cyclohexylamine, the above specificity as evidenced by NMR analysis. N, N-Bis (3-trimethoxysilylpropyldithio) -cyclohexylamine of the formula (VII-1) is obtained (appearance of an orange oil, yield 85%):
Embedded image

・¹H NMR (CDCl_Three) δ_H
0.73 (m, 4H, Si-CH_Two); 1.22 (m, 2H, CH_Two); 1.64-1.92 (m, 8H, CH_Two);
2.25 (m, 2H, CH_Two); 2.40 (m, 2H, CH_Two); 2.88 (m, 4H, SCH_Two); 3.01 (m, 1H, NCH); 3.56 (s, 18H, -OCH_Three).
・¹³C NMR (CDCl_Three) δ_C
8.3 (2xSi-CH_Two); 22.3 (2xCH_Two); 26.5 (CH_Two); 25.9 (2 x CH_Two); 32.7 (2 x CH_Two);
41.6 (2xS-CH_Two); 50.4 (-OCH_Three); 59.9 (N-CH)
That is, an organoxysilane-dithiosulfenamide of general formula (VII) was prepared as follows:
-R¹ = Cyclohexyl;
‐ Z = (CH_Two)_Three (propylene);
-R^Four = Methyl;
‐ A = 3
Embodiment 4
[0046]
The same procedure is performed as in Example 3, but by substituting 3-mercaptopropyltrimethoxysilane with 3-mercaptopropyltriethoxysilane, as evidenced by NMR analysis, the specific formula (VII-2) ) Of N, N-bis (3-triethoxysilylpropyldithio) cyclohexylamine (orange oil appearance, 90% yield):
Embedded image

・¹H NMR (CDCl_Three) δ_H
0.75 (t, 4H, Si-CH_Two); 1.21 (m, 20H, 6xCH_Three and CH_Two); 1.62-1.91 (m, 8H, CH_Two); 2.25 (m, 2H, CH_Two); 2.40 (m, 2H, CH_Two); 2.89 (t, 4H, SCH_Two); 3.01 (m, 1H, NCH); 3.81 (q, 12H, -OCH_Two)
・¹³C NMR (CDCl_Three) δ_C
9.6 (2xSi-CH_Two); 18.1 (2xCH_Three); 22.3 (2xCH_Two); 26.5 (CH_Two); 26.0 (2 x CH_Two);
32.7 (2 x CH_Two); 41.5 (S-CH_Two); 58.3 (-OCH_Two); 59.8 (N-CH)
Embodiment 5
[0047]
By performing the same procedure as in Example 3, but substituting the above cyclohexylamine with 3- (triethoxysilyl) propylamine, the N of the above specific formula (VII-3) is proved by NMR analysis. , N-Bis (3-triethoxysilylpropyldithio) -3-triethoxysilylpropylamine (yellow oily appearance, 87% yield) is obtained:
Embedded image

・¹H NMR (CDCl_Three) δ_H
0.62 (t, 2H, Si-CH_Two); 0.74 (t, 4H, Si-CH_Two); 1.22 (t, 9H, CH_Three-CH_Two-O);
1.67 (m, 2H, CH_Two); 1.83 (m, 4H, CH_Two); 2.82 (t, 4H, S-CH_Two);
3.05 (m, 2H, CH_Two); 3.55 (s, 18H, O-CH_Three); 3.80 (q, 6H, -OCH_Two).
・¹³C NMR (CDCl_Three) δ_C
6.2 (Si-CH_Two); 9.7 (Si-CH_Two); 18.4 (CH_Three-CH_Two); 20.9 (CH_Two); 23.8 (CH_Two);
44.0 (S-CH_Two); 50.6 (-OCH_Three); 54.9 (N-CH_Two); 58.5 (-OCH_Two)
Embodiment 6
[0048]
In this test, N-methyl-N- (3'-triethoxysilylpropyldithio) -3'-trimethoxysilylpropylamine of formula (V-3) is synthesized in three steps.
a)Phthalimidosulfenyl chloride:
A 0.1 mole (35.6 g) suspension of phthalimide disulfide in 350 ml chloroform in a three-necked flask equipped with a magnetic stirrer is heated to 60 ° C. A stream of chlorine gas is passed until complete dissolution has occurred. The reaction medium is returned to ambient temperature and the solvent is evaporated off under reduced pressure. The obtained phthalimidosulphenyl chloride is recrystallized in dichloromethane.
Yield; 99%
Appearance: yellow crystal
Melting point: 114 ° C
¹H NMR (CDCl_Three) δ_H :
7.90 (m, aromatic 2H); 8.01 (m, aromatic 2H).
¹³C NMR (CDCl_Three) δ_C:
124.7 (2 aromatic C); 131.6 (2 aromatic C);
135.6 (2 CH aromatic); 165.8 (2 C = O).
b)N- (N'- Methyl -N'-3- Trimethoxysilylpropyl ) Aminothiophthalimide:
The above phthalimidosulphenyl chloride (0.1 mol, ie 21.35 g) is dissolved in 350 ml of chloroform in a three-necked flask equipped with a magnetic stirrer under an inert atmosphere. 0.21 mol of N-methyl-N- (3-trimethoxysilylpropyl) amine diluted in 50 ml of chloroform is added dropwise at ambient temperature. The mixture is stirred for 3 hours, then the solvent is evaporated. The mixture is treated with diethyl ether and the chlorohydrate of the amine is filtered and then concentrated under reduced pressure.
Yield: 88%
Appearance: orange oil
¹H NMR (CDCl_Three) δ_H
0.64 (t, 2H, Si-CH_Two); 1.78 (m, 2H, CH_Two); 2.93 (H_ThreeC-N);
3.05 (t, 2H N- CH_Two); 3.56 (s, 9H -OCH_Three); 7.77 (m, aromatic 2H);
7.92 (m, aromatic 2H).
¹³C NMR (CDCl_Three) δ_c
5.9 (SiCH_Two); 21.0 (CH_Two); 46.8 (N-CH_Three); 50.5 (-OCH_Three);
62.9 (N-CH_Two); 123.8 (2 aromatic C); 132.3 (2 aromatic C);
134.2 (2 aromatic CH); 169.5 (2 C = O)
[0049]
c)N- Methyl -N- (3'- Triethoxysilylpropyldithio ) -3'- Trimethoxysilylpropylamine:
The sulfide (50 mmol) obtained in the above step is dissolved in 250 ml of benzene in a three-necked flask equipped with a magnetic stirrer in an inert atmosphere. 3-mercaptopropyltriethoxysilane (45 mmol) diluted in a minimum amount of benzene is added in one portion. This is left for 48 hours with stirring at ambient temperature. The precipitated phthalimide and excess sulfide were filtered off, and the solvent was evaporated under reduced pressure.
As evidenced by NMR analysis, N-methyl-N- (3′-triethoxysilylpropyldithio) -3′-trimethoxysilylpropylamine of specific formula (V-3) described above (the appearance of a yellow oil). , Yield 95%):
Embedded image

・¹H NMR (CDCl_Three) δ_H
0.61 (t, 2H, Si-CH_Two); 0.72 (t, 2H, Si-CH_Two); 1.22 (t, 9H, CH_Three); 1.68 (m, 2H, CH_Two); 1.80 (m, 2H, CH_Two); 2.68 (NCH_Three); 2.75 (t, 2H, CH_Two); 2.88 (t, 2H, CH_Two); 3.57 (s, 9H, -OCH_Three); 3.82 (q, 6H, O-CH_Two).
・¹³C NMR (CDCl_Three) δ_C
6.2 (Si-CH_Two); 9.7 (Si-CH_Two); 18.4 (CH_Three-CH_Two); 20.9 (CH_Two); 23.8 (CH_Two);
44.0 (S-CH_Two); 46.1 (-NCH_Three); 50.6 (-OCH_Three); 58.5 (-OCH_Two); 60.9 (N-CH_Two)
That is, dithiosulfenamide organooxysilane of the general formula (V) was obtained as follows:
-R¹ = Methyl;
-R^Two = − Z − Si (OMe)_Three;
‐ Z = (CH_Two)_Three (propylene);
-R^Four = Methyl; R⁶ = Ethyl;
‐ A = b = 3
[0050]
III-2. Preparation of rubber composition
In each of the following tests, the procedure is as follows: the diene elastomer (or diene elastomer mixture as needed), reinforcing filler, coupling agent, and then, after kneading for 1-2 minutes, Add various additives other than the sulfur system to the internal mixer and fill up to 70%. The initial tank temperature of the mixer is about 60 ° C. Thereafter, thermomechanical processing (non-production stage) is performed in two steps until a maximum "fall" temperature of about 165 ° C. is reached (total kneading time about 7 minutes). The mixture thus obtained is collected, cooled, and then the vulcanization system (sulfur and sulfenamide accelerator) is mixed with an open mixer (homo-finisher) at 30 ° C. for 3-4 minutes. (Production step).
The composition thus obtained is then cut and / or assembled in the form of a thin rubber slab (2-3 mm thick) or a thin sheet for measuring its physical or mechanical properties or in the desired dimensions. Thereafter, it is calendered, for example, into shaped elements that can be used directly as semi-finished products for tires, in particular treads for tires.
In the following tests, the reinforcing inorganic filler (HD silica) makes up the entire reinforcing filler used in the preferred amount in the range of 50 to 100 phr; however, one part of the reinforcing filler, preferably small It is obvious for a person skilled in the art that the proportion can be replaced by carbon black.
[0051]
III-3. Characterization of rubber composition
The purpose of this test was to illustrate the improved (inorganic filler / diene elastomer) coupling performance in the composition according to the invention compared to the prior art composition using a conventional TESPT coupling agent. is there.
-Composition C-1: Normal TESPT silane
-Composition C-2: a silane-dithiosulfenamide of the formula VII-2.
TESPT has the formula: [(C_TwoH_FiveO)_ThreeSi (CH_Two)_ThreeS_Two]_TwoRecognize that it is a bis (3-triethoxysilylpropyl) tetrasulfide having the formula: TESPT is supported, for example, by Degussa under the trade name "Si69" (or up to 50% by weight on carbon black) In some cases, it is commercially available as “X50S”) or from Witco under the trade name “Silquest A1289” (both polysulfide S having an average x value close to 4)._xCommercially available mixture).
The structure of TESPT is as follows:
Embedded image

This formula should be compared to the formula for dithiosulfenamidosilane of formula VII-1 below:
Embedded image

Part of the two chemical structures is identical (Y functional group and hydrocarbon group Z (in this case, a propylene chain), allowing the bonding of Y and X), the only difference is that on the diene elastomer The essence of the sulfurated functional groups (X-functional groups) that can be grafted onto is: polysulfide groups Sx for conventional compositions and polythiosulfenamide groups for the compositions of the invention.
[0052]
Table 1 shows the formulation of the two compositions (the quantities of the various products are expressed in phr); the vulcanization system consists of sulfur and sulfenamide.
The two coupling agents are used in this case in equimolar amounts of silicon, i.e., irrespective of the composition, the Y-functionality which is reactive towards silica and its hydroxyl surface groups (this Then Y = Si (OEt)_Three) Are used in the same moles.
For the amount of reinforcing inorganic filler, the amount of coupling agent is both less than 10 phr, which amounts to less than 15% by weight, based on the amount of reinforcing inorganic filler.
Figures 1 and 2 show the rheogram (torque (dN.m) as a function of cure time (min) and modulus (MPa) curve as a function of elongation (%) after cure (40 min at 150 ° C), respectively. These curves are marked as C1 and C2 in FIG. 1 and as C1 ′ and C2 ′ in FIG. 2 and correspond to compositions C-1 and C-2, respectively.
First of all, the rheogram of FIG. 1 clearly shows the advantage of the composition C-2 according to the invention: close to the induction time of the control composition (7.5 minutes after measurement according to section I-3 above) Induction period (5.1 min); maximum torque (19 dN.m) greater than the maximum torque of the control composition (18 dN.m after measurement); finally, above all, at a conversion of 30% to 80% Clearly faster vulcanization rates (measured (according to section I-3 above) were recorded in composition C-2, in the control composition, as exemplified by the rheogram slope (constant K), which is clearly noticeable. Slope (K = 0.13 min^-1) Of K = 0.22 min^-1In other words, curing of the composition C-2 can be performed in a shorter time.
After curing (FIG. 2), the composition of the invention (curve C2) has substantially the same properties at break as compared to the control composition (curve C1); Reinforcement (modulus) values clearly superior in elongation); as elongation increases, the distance between the two curves all becomes more pronounced. Such behavior clearly illustrates the improved coupling between the reinforcing inorganic filler and the diene elastomer, making it possible to expect the very good ability of the compositions according to the invention to withstand abrasion. I have.
Furthermore, the already low Mooney plasticity in the control composition is unexpectedly reduced in the composition according to the invention (close to 10%), and another advantage is the unvulcanized state of the composition according to the invention. Has demonstrated excellent processing capabilities.
[Industrial applicability]
[0053]
In conclusion, the coupling agents selected for the compositions according to the invention give later high reinforcing properties, excellent processing properties in the uncured state and a very good vulcanizing capacity, such as reinforcing silica. It demonstrates an overall higher efficacy than TESPT, which is still considered as a reference (inorganic filler / elastomer) coupling agent in diene rubber compositions reinforced with various inorganic fillers.
The present invention relates to a rubber composition intended for the production of treads for tires having both low rolling resistance and high wear resistance, in particular those treads such as passenger vehicles, motorcycles or heavy vehicle types. It can be applied particularly advantageously when intended for tires for industrial vehicles.
[0054]
table 1

(1) SSBR containing 59.5% 1-2 polybutadiene units and 26.5% styrene; Tg = -29 ° C;
75 phr dry SBR bulking with aromatic oil (SSBR + total oil equals 103 phr).
(2) BR containing 4.3% 1-2, 2.7% trans, 93% cis 1-4 (Tg = -106 ° C).
(3) Micro-bead type silica type “HDS” from Rhodia-Zeosil 1165 MP
(BET and CTAB: about 150-160 m^Two/ g).
(4) TESPT (“Si69” from Degussa).
(5) Silane-dithiosulfenamides of formula VII-2 (Section III-1, synthesized according to Example 4);
(6) Diphenylguanidine (“Vulcacit D” from Bayer).
(7) N-cyclohexyl-2-benzothiazylsulfenamide (available from Flexsys)
“Santocure CBS”).
[Brief description of the drawings]
[0055]
FIG. 1 is a rheogram (curing curve) recorded in a rubber composition according to the invention or not.
FIG. 2 is a curve of the change in modulus as a function of elongation for these rubber compositions.

Claims (46)

At least (i) a diene elastomer, (ii) an inorganic filler as a reinforcing filler, and (iii) a (inorganic filler / diene elastomer) coupling agent, at least bifunctional, and Elastomer compositions useful in the manufacture of tires based on polysilylated organosilicon compounds that can be grafted onto the elastomer by a sulfur group having a sulfenamide functionality:
(I) ≡ Si − A − S _x − NR ¹ R ²
Wherein A is a linear or branched divalent linking group that allows the polythiosulfenamide group to be linked to the first silicon atom of the organosilicon compound;
x is an integer or a fraction of 2 to 4;
R ¹ represents hydrogen, a monovalent hydrocarbon group or R ² ;
R ² represents the following group;
− B − Si ≡
B is a linear or branched divalent group;
Si represents the second silicon atom of the organosilicon compound). R ¹ consists of hydrogen, C ₁ -C ₈ alkyl, C ₅ -C ₁₀ cycloalkyl, C ₆ -C ₁₈ aryl, (C ₆ -C ₁₈ ) aryl- (C ₁ -C ₈ ) alkyl and R ² The composition of claim 1, wherein the composition is selected from the group. R ¹ is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, hexyl, benzyl, cyclohexyl, selected from the group consisting of phenyl and R ^2, The composition of claim 2. R ² represents a group of the following set forth in any one composition of claims 1 to 3:
− B − Si R ³ _(3-a) (OR ⁴ ) _a
(Wherein, R ³ represents a monovalent hydrocarbon group;
R ⁴ represents hydrogen or a monovalent hydrocarbon group which may be the same or different from R ³ ;
a is an integer equal to 1, 2 or 3). Groups R ³ and R ^4, C ₁ -C ₈ alkyl, selected from the C ₅ -C ₁₀ cycloalkyl and phenyl, composition of claim 4. Groups R ³ and R ⁴ are selected from among C ₁ -C ₄ alkyl, composition of claim 5. 7. A compound according to any one of claims 1 to 6, wherein A and B may be the same or different and represent a hydrocarbon group containing 1 to 18 carbon atoms and optionally one or more heteroatoms. Composition. A and B, and may be identical or be different, C ₁ -C ₁₈ selected from alkylene and C ₆ -C ₁₂ arylene, composition of claim 7. 9. The composition of claim 8, wherein said sulfur group has the following specific formula:
(II) ≡ Si − Z − S _x − NR ¹ − Z − Si ≡
Wherein the groups Z may be the same or different and represent C ₁ -C ₈ alkylene. 9. The composition of claim 8, wherein said sulfur group has the following specific formula:
(III) ≡ Si − Z − S _x − NR ¹ − S _y − Z − Si ≡
(Wherein the group Z can be the same or different and represents C ₁ -C ₈ alkylene; y can be the same or different than x and is an integer or fraction of 2-4). The composition according to any one of claims 1 to 10, wherein the diene elastomer is selected from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. object. The composition according to any one of claims 1 to 11, comprising 10 to 200 phr (parts by mass per 100 parts by mass of elastomer) of a reinforcing inorganic filler. The composition according to any one of claims 1 to 12, wherein the amount of the coupling agent is 1 to 20 phr. 14. The composition according to any one of claims 1 to 13, wherein the organosilicon compound is a silane-polythiosulfenamide of the formula:
(IV) (R ⁶ O) _b R ⁵ _(3-b) Si − A − S _x − NR ¹ − B − Si R ³ _(3-a) (OR ⁴ ) _a
(Wherein, R ⁵ represents a monovalent hydrocarbon group;
R ⁶ represents hydrogen or a monovalent hydrocarbon group which may be the same or different from R ⁵ ;
b is an integer equal to 1, 2 or 3;
R ⁵ , R ⁶ and b can be the same or different from R ³ , R ⁴ and a, respectively). 15. The composition of claim 14, wherein the silane has the following specific formula:
(V) (R ⁶ O) _b R ⁵ _(3-b) Si − Z − S _x − NR ¹ − Z − Si R ³ _(3-a) (OR ⁴ ) _a
Wherein the groups Z can be the same or different and represent C ₁ -C ₄ alkylene; the groups R ³ , R ⁴ , R ⁵ and R ⁶ represent C ₁ -C ₃ alkyl. 15. The composition of claim 14, wherein the silane has the following specific formula:
(VI) (R ⁶ O) _b R ⁵ _(3-b) Si − Z − S _x − NR ¹ − S _y − Z − Si R ³ _(3-a) (OR ⁴ ) _a
Wherein the groups Z may be the same or different and represent C ₁ -C ₄ alkylene; the groups R ³ , R ⁴ , R ⁵ and R ⁶ represent C ₁ -C ₃ alkyl; , X, which may be the same or different and is an integer or fraction of 2 to 4). 17. The composition of claim 16, wherein said silane has the following symmetric formula:
(VII) [(R ⁴ O) _a R ³ _(3-a) Si − Z − S _x −] ₂ NR ¹ Z is ^{propylene; R 3, R 4, R} 5 and R ⁶ are selected from among methyl and ethyl, composition of any one of claims 15 to 17. R ¹ is hydrogen, methyl, ethyl, propyl, isopropyl, hexyl, benzyl, selected from the group consisting of cyclohexyl and phenyl, any one composition according to claim 14 to 18. 20. The composition according to any one of the preceding claims, wherein x and, where applicable, y are integers or fractions of 2-3. 21. The composition of claim 20, wherein x and y, where applicable, are equal to two. The composition according to any one of claims 1 to 21, wherein the amount of the coupling agent represents 0.5% by mass to 20% by mass based on the amount of the reinforcing inorganic filler. The composition according to any one of claims 1 to 22, wherein the reinforcing inorganic filler is mainly silica. 24. The composition of claim 23, wherein said reinforcing inorganic filler comprises the entire reinforcing filler. 24. The composition according to claim 1, wherein the reinforcing inorganic filler is used in a mixture with carbon black. 26. The composition of claim 25, wherein the carbon black is present in an amount from 2 to 20 phr. The diene elastomer has a styrene content of 20% to 30% by weight, a vinyl bond content of a butadiene fraction of 15% to 65%, a trans-1,4 bond content of 20% to 75%, and -20 ° C. 27. The composition according to any one of claims 11 to 26, which is a butadiene-styrene copolymer (SBR) having a glass transition temperature of -55C. 28. The composition of claim 27, wherein said SBR is SBR prepared in solution (SSBR). 29. The composition according to claim 27 or 28, wherein said SBR is used in a mixture with polybutadiene. 30. The composition of claim 29, wherein said polybutadiene has more than 90% cis-1,4 bonds. 27. The composition according to any one of claims 11 to 26, wherein the diene elastomer is an isoprene elastomer, preferably natural rubber or synthetic cis-1,4 polyisoprene. The composition according to any one of claims 1 to 31, which is in a vulcanized state. Each of the following steps:
-In a mixer, in a diene elastomer, at least:
-Inorganic filler for reinforcement,
-A polysilylated organosilicon compound which is at least bifunctional and can be grafted onto the elastomer by a sulfur group, as a (inorganic filler / diene elastomer) coupling agent,
Mixing step;
Thermomechanically kneading the whole mixture in one or more steps until a maximum temperature of 110 ° C. to 190 ° C. is reached;
Cooling the whole mixture to a temperature below 100 ° C .;
・ Next, a step of mixing a vulcanization system;
Kneading the entire mixture until a maximum temperature of less than 120 ° C. is reached;
Wherein the sulfur group comprises a polythiosulfenamide functional group and satisfies the following formula: A method for producing an elastomer composition useful for producing tires:
(I) ≡ Si − A − S _x − NR ¹ R ²
Wherein A is a linear or branched divalent linking group that allows the polythiosulfenamide group to be linked to the first silicon atom of the organosilicon compound;
x is an integer or a fraction of 2 to 4;
R ¹ represents hydrogen, a monovalent hydrocarbon group or R ² ;
R ² represents the following group;
− B − Si ≡
B is a linear or branched divalent linking group;
Si represents the second silicon atom of the organosilicon compound). R ² represents a group of following claim 33, wherein the method:
− B − Si R ³ _(3-a) (OR ⁴ ) _a
(Wherein, R ³ represents a monovalent hydrocarbon group;
R ⁴ represents hydrogen or a monovalent hydrocarbon group which may be the same or different from R ³ ;
a is an integer equal to 1, 2 or 3). 35. The method of claim 34, wherein said organosilicon compound is a silane polythiosulfenamide of the formula:
(IV) (R ⁶ O) _b R ⁵ _(3-b) Si − A − S _x − NR ¹ − B − Si R ³ _(3-a) (OR ⁴ ) _a
(Wherein, R ⁵ represents a monovalent hydrocarbon group;
R ⁶ represents hydrogen or a monovalent hydrocarbon group which may be the same or different from R ⁵ ;
b is an integer equal to 1, 2 or 3;
R ⁵ , R ⁶ and b can be the same or different from R ³ , R ⁴ and a, respectively). 36. The method of claim 35, wherein the silane satisfies the following specific formula:
(V) (R ⁶ O) _b R ⁵ _(3-b) Si − Z − S _x − NR ¹ − Z − Si R ³ _(3-a) (OR ⁴ ) _a
Wherein the groups Z can be the same or different and represent C ₁ -C ₄ alkylene; the groups R ³ , R ⁴ , R ⁵ and R ⁶ represent C ₁ -C ₃ alkyl. 37. The method of claim 36, wherein the silane satisfies the following specific formula:
(VI) (R ⁶ O) _b R ⁵ _(3-b) Si − Z − S _x − NR ¹ − S _y − Z − Si R ³ _(3-a) (OR ⁴ ) _a
Wherein the groups Z may be the same or different and represent C ₁ -C ₄ alkylene; the groups R ³ , R ⁴ , R ⁵ and R ⁶ represent C ₁ -C ₃ alkyl; , X, which may be the same or different and is an integer or fraction of 2 to 4). Use of the composition according to any one of claims 1 to 32 in the manufacture of tires or semi-finished products for tires. Semi-finished product for tires selected from the group consisting of treads, underlayers, crown reinforcement plies, sidewalls, carcass reinforcement plies, beads, protectors, internal tubes and hermetic internal rubber for tubeless tires 39. Use according to claim 38 in the manufacture of A tire comprising the rubber composition according to claim 1. A semi-finished product for a tire, comprising the rubber composition according to any one of claims 1 to 32. 42. The tread, underlayer, crown reinforcement plies, sidewalls, carcass reinforcement plies, beads, protectors, inner tubes and hermetic inner rubber for tubeless tires. Rubber semi-finished products. 43. The semi-finished product of claim 42, comprising a tire tread. The tire tread according to claim 43, comprising the rubber composition according to any one of claims 27 to 31. In a composition based on a diene elastomer reinforced by an inorganic filler intended for the manufacture of tires, an inorganic filler of a polysilylated organosilicon compound which is at least bifunctional and can be grafted onto said elastomer by means of sulfur groups. / Diene elastomer) use as a coupling agent, wherein the sulfur group comprises a polythiosulfenamide functional group and satisfies the following formula:
(I) ≡ Si − A − S _x − NR ¹ R ²
Wherein A is a linear or branched divalent linking group that allows the polythiosulfenamide group to be linked to the first silicon atom of the organosilicon compound;
x is an integer or a fraction of 2 to 4;
R ¹ represents hydrogen, a monovalent hydrocarbon group or R ² ;
R ² represents the following group;
− B − Si ≡
B is a linear or branched divalent linking group;
Si represents the second silicon atom of the organosilicon compound). Each of the following steps:
-In a mixer, in a diene elastomer, at least:
-Inorganic filler for reinforcement,
-A polysilylated organosilicon compound which is at least bifunctional and can be grafted onto the elastomer by a sulfur group, as a (inorganic filler / diene elastomer) coupling agent,
Mixing step;
Thermomechanically kneading the whole mixture in one or more steps until a maximum temperature of 110 ° C. to 190 ° C. is reached;
Cooling the whole mixture to a temperature below 100 ° C .;
Wherein the sulfur group comprises a polythiosulfenamide functional group and satisfies the following formula:
(I) ≡ Si − A − S _x − NR ¹ R ²
Wherein A is a linear or branched divalent linking group that allows the polythiosulfenamide group to be linked to the first silicon atom of the organosilicon compound;
x is an integer or a fraction of 2 to 4;
R ¹ represents hydrogen, a monovalent hydrocarbon group or R ² ;
R ² represents the following group;
− B − Si ≡
B is a linear or branched divalent linking group;
Si represents the second silicon atom of the organosilicon compound).

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